Question: "A hypothesis test yields a P-value of 0.20." Which of the following best describes what is meant by this statement?

Choices:
- The probability of getting a finding at least as extreme as that obtained by chance alone if the null hypothesis is true is 0.20.
- The probability of getting a finding as extreme as that obtained by chance alone from repeated random sampling is 0.20.
- The probability is 0.20 that our finding is significant.
- The probability of getting this finding is 0.20.


Question: Which of the following is not true with regard to contingency tables for chi-square tests for independence?

Choices:
- The categories are not numerical for either variable.
- Observed frequencies should be whole numbers.
- Expected frequencies should be whole numbers.
- Expected frequencies in each cell should be at least 5, and to achieve this, one sometimes combines categories for one or the other or both of the variables.


Question: The observed times (in minutes) it takes a runner to complete a marathon are normally distributed. The z-score for his running time this week is –2. Which one of the following statements is a correct interpretation of his z-score?

Choices:
- This week his time was two minutes lower than his time last week.
- This week his time was two minutes lower than his best time ever.
- This week his time was two minutes lower than his average time.
- This week his time was two standard deviations lower than his average time.


Question: The mean Law School Aptitude Test (LSAT) score for applicants to a particular law school is 650 with a standard deviation of 45. Suppose that only applicants with scores above 700 are considered. What percentage of the applicants considered have scores below 740? (Assume the scores are normally distributed.)

Choices:
- 13.3%
- 17.1%
- 82.9%
- 86.7%


Question: On the same test, Mary and Pam scored at the 64th and 56th percentiles, respectively. Which of the following is a true statement?

Choices:
- Mary scored eight more points than Pam.
- Mary's score is 8% higher than Pam's.
- Eight percent of those who took the test scored between Pam and Mary.
- Thirty-six people scored higher than both Mary and Pam.


Question: A study looked at medical records of about 23,000 patients, mostly in Asia. They found that patients who drank at least three cups of green tea per day had a much lower incidence of depression. In an American newspaper article about this study, which of the following statements should not be made?

Choices:
- It is possible that people who drink green tea also tend to have healthier lifestyles than those who don't.
- It is possible that people who drink green tea also tend to have a more positive outlook on life than those who don't.
- Because this is observational data, the association between drinking green tea and a lower incidence of depression is not an indication of a causal relationship.
- People who want to avoid depression should consider drinking green tea on a daily basis.


Question: A researcher planning a survey of school principals in a particular state has lists of the school principals employed in each of the 125 school districts. The procedure is to obtain a random sample of principals from each of the districts rather than grouping all the lists together and obtaining a sample from the entire group. Which of the following is a correct conclusion?

Choices:
- This is a simple random sample obtained in an easier and less costly manner than procedures involving sampling from the entire population of principals.
- This is a cluster sample in which the population was divided into heterogeneous groups called clusters.
- This is an example of systematic sampling, which gives a reasonable sample as long as the original order of the list is not related to the variables under consideration.
- This is a stratified sample, which may give comparative information that a simple random sample wouldn't give.


Question: In an experiment, the control group should receive

Choices:
- treatment opposite that given the experimental group.
- the same treatment given the experimental group without knowing they are receiving the treatment.
- a procedure identical to that given the experimental group except for receiving the treatment under examination.
- a procedure identical to that given the experimental group except for a random decision on receiving the treatment under examination.


Question: Tina’s science fair project was to estimate the mean amount of chemicals in her city’s water supply. At first, she had decided to use a random sample of 15 observations. But her teacher asked her to take 35 observations. The mean and standard deviation from 35 observations turned out to be approximately the same as those from 15 observations. Is there any advantage in using 35 observations instead of 15 observations?

Choices:
- There is no advantage. Because the mean and the standard deviation are about the same, the confidence interval computed using 35 observations should be approximately the same as that computed using 15 observations.
- There is no advantage. In fact, the 20 extra observations will increase the likelihood of error.
- There is no advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be wider than that using 15 observations.
- There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations.


Question: The total cholesterol level in a large population of people is strongly skewed right with a mean of 210 mg/dL and a standard deviation of 15 mg/dL. If random samples of size 16 are repeatedly drawn from this population, which of the following appropriately describes the sampling distribution of these sample means?

Choices:
- The shape is unknown with a mean of 210 and a standard deviation of 15.
- The shape is somewhat skewed right with a mean of 210 and a standard deviation of 3.75.
- The shape is approximately normal with a mean of 210 and a standard deviation of 15.
- The shape is approximately normal with a mean of 210 and a standard deviation of 3.75.


Question: An experiment is conducted in which the response variable is the average gain in participants' performance in the long jump. A two-sample t-test with a 5% level of significance will be used to analyze the results. If all else is kept the same, which of the following descriptions of a possible change in procedure is true?

Choices:
- Change from equal size treatment groups to very different size treatment groups would increase the power of the test.
- Change from a 5% significance level to a 1% significance level would increase the power of the test.
- Taking more careful measurements to reduce variability in the response would increase the power of the test.
- Increasing the sample size would reduce the probability of a Type I error.


Question: An assembly line machine is supposed to turn out ball bearings with a diameter of 1.25 centimeters. Each morning the first 30 bearings produced are pulled and measured. If their mean diameter is under 1.23 centimeters or over 1.27 centimeters, the machinery is stopped and an engineer is called to make adjustments before production is resumed. The quality control procedure may be viewed as a hypothesis test with the null hypothesis H0: μ = 1.25 and the alternative hypothesis Ha: μ ≠ 1.25. The engineer is asked to make adjustments when the null hypothesis is rejected. In test terminology, what would a Type II error result in?

Choices:
- A warranted halt in production to adjust the machinery
- An unnecessary stoppage of the production process
- Continued production of wrong size ball bearings
- Continued production of proper size ball bearings


Question: We are interested in the proportion p of people who are unemployed in a large city. Eight percent of a simple random sample of 500 people are unemployed. What is the midpoint for a 95% confidence interval estimate of p?

Choices:
- 0.012
- 0.025
- 0.475
- None of the above.


Question: An insurance company wishes to study the number of years drivers in a large city go between automobile accidents. They plan to obtain and analyze the data from a sample of drivers. Which of the following is a true statement?

Choices:
- A reasonable time-and-cost-saving procedure would be to use systematic sampling on an available list of all AAA (Automobile Association of America) members in the city.
- A reasonable time-and-cost-saving procedure would be to randomly choose families and include all drivers in each of these families in the sample.
- To determine the mean number of years between accidents, randomness in choosing a sample of drivers is not important as long as the sample size is very large.
- None of the above are true statements.


Question: Which of the following is the central limit theorem?

Choices:
- No matter how the population is distributed, as the sample size increases, the mean of the sample means becomes closer to the mean of the population.
- No matter how the population is distributed, as the sample size increases, the standard deviation of the sample means becomes closer to the standard deviation of the population divided by the square root of the sample size.
- If the population is normally distributed, then as the sample size increases, the sampling distribution of the sample mean becomes closer to a normal distribution.
- The central limit theorem refers to something else.


Question: A manufacturer of ready-bake cake mixes is interested in designing an experiment to test the effects of four different temperature levels (300, 325, 350, and 375F), two different types of pans (glass and metal), and three different types of ovens (gas, electric, and microwave) on the texture of its cakes, in all combinations. Which of the following below is the best description of the design of the necessary experiment?

Choices:
- A completely randomized design with nine treatment groups
- A completely randomized design with 24 treatment groups
- A randomized block design, blocked on temperature, with six treatment groups
- A randomized block design, blocked on type of pan, with 12 treatment groups


Question: A study is made to determine whether more hours of academic studying leads to higher point scoring by basketball players. In surveying 50 basketball players, it is noted that the 25 who claim to study the most hours have a higher point average than the 25 who study less. Based on this study, the coach begins requiring the players to spend more time studying. Which of the following is a correct statement?

Choices:
- While this study may have its faults, it still does prove causation.
- There could well be a confounding variable responsible for the seeming relationship.
- While this is a controlled experiment, the conclusion of the coach is not justified.
- To get the athletes to study more, it would be more meaningful to have them put in more practice time on the court to boost their point averages, as higher point averages seem to be associated with more study time.


Question: Biologists around the world have increased efforts at conservation. Monitoring wildlife populations is important so that appropriate management efforts can be implemented, but such monitoring is often difficult. One study found a cheap and easy way to estimate the number of nesting sites of terns (a type of seabird) by monitoring the number of calls heard per minute. More calls happen when there are more birds, as one would expect. In fact, it turned out that the number of calls explained 71% of the variation in the abundance of nests between breeding sites. Which of the following statements is correct about the correlation between the number of calls and the abundance of nests?

Choices:
- The correlation coefficient is -0.71.
- The correlation coefficient is 0.71.
- The correlation coefficient is -0.84.
- The correlation coefficient is 0.84.


Question: A company has 1000 employees evenly distributed throughout five assembly plants. A sample of 30 employees is to be chosen as follows. Each of the five managers will be asked to place the 200 time cards of their respective employees in a bag, shake them up, and randomly draw out six names. The six names from each plant will be put together to make up the sample. Will this method result in a simple random sample of the 1000 employees?

Choices:
- Yes, because every employee has the same chance of being selected.
- Yes, because every plant is equally represented.
- Yes, because this is an example of stratified sampling, which is a special case of simple random sampling.
- No, because not every group of 30 employees has the same chance of being selected.


Question: A doctor hopes that a new surgery technique will shorten the recovery time compared to the standard technique. To test this, he designed an experiment in which patients who required this type of surgery were randomly assigned to the standard technique or the new technique. Then the mean recovery time for each treatment group was compared. Assuming conditions for inference were met, which analysis should be used?

Choices:
- A t-test for a mean.
- A t-test for a difference in means.
- A z-test for a mean.
- A z-test for a difference in means.


Question: A researcher plans a study to examine long-term confidence in the U.S. economy among the adult population. She obtains a simple random sample of 30 adults as they leave a Wall Street office building one weekday afternoon. All but two of the adults agree to participate in the survey. Which of the following conclusions is correct?

Choices:
- Proper use of chance as evidenced by the simple random sample makes this a well-designed survey.
- The high response rate makes this a well-designed survey.
- Selection bias makes this a poorly designed survey.
- A voluntary response study like this gives too much emphasis to persons with strong opinions.


Question: To study the effect of music on piecework output at a clothing manufacturer, two experimental treatments are planned: day-long classical music for one group versus day-long light rock music for another. Which one of the following groups would serve best as a control for this study?

Choices:
- A third group for which no music is played
- A third group that randomly hears either classical or light rock music each day
- A third group that hears day-long R & B music
- A third group that hears classical music every morning and light rock every afternoon


Question: During the years 1886 through 2000 there were an average of 8.7 tropical cyclones per year, of which an average of 5.1 became hurricanes. Assuming that the probability of any cyclone becoming a hurricane is independent of what happens to any other cyclone, if there are five cyclones in one year, what is the probability that at least three become hurricanes?

Choices:
- 0.313
- 0.345
- 0.586
- 0.658


Question: A chi-squared test of independence is to be performed on a 3 × 4 contingency table. How many degrees of freedom does this test have?

Choices:
- 6
- 8
- 10
- 11


Question: At a large hospital, the durations of emergency room visits, from check-in to discharge, are approximately normally distributed with a mean of 167 minutes and a standard deviation of 76 minutes. Which interval, to the nearest minute, contains the middle 80% of durations?

Choices:
- 15 minutes to 319 minutes
- 53 minutes to 281 minutes
- 70 minutes to 264 minutes
- 91 minutes to 243 minutes


Question: The relation between studying time (in hours) and grade on a final exam (0-100) in a random sample of students in math class was found to be Grade = 50.25 + 10.2 (h) How will a student’s grade be affected if she studies for two hours?

Choices:
- Her grade will go up by 40.05 points.
- Her grade will go up by 20.4 points.
- Her grade will remain unchanged.
- Her grade will down by 10.2 points.


Question: A producer of skin care products has created a new formula for its cream to cure acne. To compare the effectiveness of the new cream to that of the old cream, it conducted a double-blind randomized experiment. Volunteers with acne tried the old formula on one side of their face and the new formula on the other, and which side got which formula was determined randomly. The response variable was the difference in the number of pimples (old formula - new formula). Which is the correct significance test to perform?

Choices:
- A two-proportion z-test
- A two-sample t-test
- A matched pairs t-test
- A chi-square test of independence


Question: A pharmaceutical company wants to test a new cholesterol-reducing drug against the previous drug. It does not anticipate much association between cholesterol level and gender, but it does anticipate an association between cholesterol level and the amount of exercise a person gets. For a randomized block design, it should:

Choices:
- Block on gender because it is not associated with cholesterol level.
- Block on gender because males and females are different.
- Block on the type of drug because it may be associated with cholesterol level.
- Block on exercise level because it is associated with cholesterol level.


Question: An experiment is to be conducted to determine whether taking fish oil capsules or garlic capsules has more of an effect on cholesterol levels. In past studies it was noted that daily exercise intensity (low, moderate, high) is associated with cholesterol level, but average sleep length (< 5, 5 - 8, > 8 hours) is not associated with cholesterol level. This experiment should be done

Choices:
- by blocking on exercise intensity
- by blocking on sleep length
- by blocking on cholesterol level
- by blocking on capsule type


Question: A test for heartworm in dogs shows a positive result in 96% of dogs that actually have heartworm, and shows a negative result in 98% of dogs with no heartworm. If heartworm actually occurs in 10% of dogs, what is the probability that a randomly selected dog that tested positive for heartworm actually has heartworm?

Choices:
- 11%
- 18%
- 84%
- 88%


Question: Suppose X and Y are random variables with μx = 32, σx = 5, μy = 44, and σy = 12. Given that X and Y are independent, what are the mean and standard deviation of the random variable X + Y?

Choices:
- μx+y = 76, σx+y = 8.5
- μx+y = 76, σx+y = 13
- μx+y = 76, σx+y = 17
- μx+y = 38, σx+y = 17


Question: A high school sent a survey to a randomly selected sample of 75 of last year's graduating class. 27 of those selected did not return the survey. The best plan of action would be to:

Choices:
- Use the surveys that were returned and change the sample size to 48 for the analysis.
- Use the surveys that were returned and leave the sample size at 75 for the analysis.
- Randomly select 27 additional class members and send the survey to them.
- Follow up with those that did not return the survey to encourage them to respond.


Question: Mr. Bee's statistics class had a standard deviation of 11.2 on a standardized test, while Mr. Em's class had a standard deviation of 5.6 on the same test. Which of the following is the most reasonable conclusion concerning the two classes' performance on the test?

Choices:
- Mr. Bee's class is less heterogeneous than Mr. Em's.
- Mr. Em's class is more homogeneous than Mr. Bee's.
- Mr. Bee's class performed twice as well as Mr. Em's.
- Mr. Em's class did not do as well as Mr. Bee's.


Question: When a patient complains to the doctor about a certain set of symptoms, the doctor diagnoses the patient with Condition A 15% of the time. If a patient with these symptoms is diagnosed with Condition A, he or she is diagnosed with Condition B 70% of the time. A patient with these symptoms that is not diagnosed with Condition A is diagnosed with Condition B 10% of the time. What is the probability that a patient with this set of symptoms will be diagnosed with at least one of these conditions?

Choices:
- 0.235
- 0.25
- 0.765
- 0.85


Question: A simple random sample is defined by

Choices:
- the method of selection.
- examination of the outcome.
- both of the above.
- how representative the sample is of the population.


Question: In one study on the effect that eating meat products has on weight level, an SRS of 500 subjects who admitted to eating meat at least once a day had their weights compared with those of an independent SRS of 500 people who claimed to be vegetarians. In a second study, an SRS of 500 subjects were served at least one meat meal per day for 6 months, while an independent SRS of 500 others were chosen to receive a strictly vegetarian diet for 6 months, with weights compared after 6 months.

Choices:
- The first study is a controlled experiment, while the second is an observational study.
- The first study is an observational study, while the second is a controlled experiment.
- Both studies are controlled experiments.
- Both studies are observational studies.


Question: Which of these is a correct description of the term?

Choices:
- A factor is a response variable.
- Replication means the experiment should be repeated several times.
- Levels are the same as treatments.
- Experimental units are the same as subjects.


Question: In the jury pool available for this week, 30 percent of potential jurors are women. A particular trial requires that, out of a jury of 12, at least three are women. If a jury of 12 is to be selected at random from the pool, what is the probability it meets the requirements of this trial?

Choices:
- 0.168
- 0.843
- 0.915
- The answer cannot be determined without knowing the size of the jury pool.


Question: An employment placement agency specializes in placing workers in jobs suited for them. From past experience, the agency knows that 20% of all the workers it places will no longer be at the position in which they were placed after one year; however, only 5% of those remaining after the first year leave during the next year. At the start of a year an employer hires 100 workers using this agency, then at the start of the next year the employer hires 100 more. How many of these 200 workers are expected to be on the job at the end of the second year?

Choices:
- 140
- 144
- 152
- 156


Question: A newspaper reporter examined police reports of accidents during the past 12 months to collect data about the speed of a car and its stopping distance. The reporter then constructed a scatterplot and computed a correlation coefficient to show the relation between a car’s speed and its stopping distance. This is an example of

Choices:
- a double-blind study
- a single-blind study
- a study involving no blinding at all
- an observational study


Question: In which of the following situations is a binomial model not an appropriate model to describe the outcome?

Choices:
- The number of heads in three tosses of a coin
- The number of rainy days in a given week
- The number of girls in a family of five children
- The number of students present in a class of 22


Question: Two possible wordings for a questionnaire on a proposed school budget increase are as follows:

Choices:
- The first showed 58% and the second 13% because of the lack of randomization as evidenced by the wording of the questions.
- The first showed 13% and the second 58% because of a placebo effect due to the wording of the questions.
- The first showed 58% and the second 13% because of the lack of a control group.
- The first showed 58% and the second 13% because of response bias due to the wording of the questions.


Question: Company I manufactures demolition fuses that burn an average of 50 minutes with a standard deviation of 10 minutes, while company II advertises fuses that burn an average of 55 minutes with a standard deviation of 5 minutes. Which company's fuse is more likely to last at least 1 hour? Assume normal distributions of fuse times.

Choices:
- Company I's, because of its greater standard deviation
- Company II's, because of its greater mean
- For both companies, the probability that a fuse will last at least 1 hour is 0.159
- For both companies, the probability that a fuse will last at least 1 hour is 0.841


Question: In a random sample of Toyota car owners, 83 out of 112 said they were satisfied with the Toyota front-wheel drive, while in a similar survey of Subaru owners, 76 out of 81 said they were satisfied with the Subaru four-wheel drive. A 90% confidence interval estimate for the difference in proportions between Toyota and Subaru car owners who are satisfied with their drive systems is reported to be -0.197 ± 0.081. Which is a proper conclusion?

Choices:
- The interval is invalid because probabilities cannot be negative.
- The interval is invalid because it does not contain zero.
- Subaru owners are approximately 19.7% more satisfied with their drive systems than are Toyota owners.
- We are 90% confident that the difference in proportions between Toyota and Subaru car owners who are satisfied with their drive systems is between -0.278 and -0.116.


Question: Which of the following statements about the correlation coefficient is true?

Choices:
- The correlation coefficient and the slope of the regression line may have opposite signs.
- A correlation of 1 indicates a perfect cause-and-effect relationship between the variables.
- Correlations of +0.87 and -0.87 indicate the same degree of clustering around the regression line.
- Correlation applies equally well to quantitative and categorical data.


Question: A school board of a large school district is proposing a new dress code for students. Some students feel that this dress code unfairly targets female students. To see if there is a difference between boys and girls in their opposition to the new dress code, they conduct a poll of 60 randomly selected male and 70 randomly selected female high school students in the district. They find that 66 females oppose the dress code and 50 males oppose the dress code. Which of the following explains why a two-proportion z-test is not appropriate?

Choices:
- The sample sizes are different.
- The sample sizes are too large.
- The number of successes and the number of failures for the two groups are not all large enough.
- The shapes of the population distributions are not known.


Question: A soft drink dispenser can be adjusted to deliver any fixed number of ounces. If the machine is operating with a standard deviation in delivery equal to 0.3 ounce, what should be the mean setting so that a 12-ounce cup will overflow less than 1% of the time? Assume a normal distribution for ounces delivered.

Choices:
- 12 - 0.99(0.3) ounces
- 12 - 2.326(0.3) ounces
- 12 - 2.576(0.3) ounces
- 12 + 2.326(0.3) ounces


Question: The average number of calories in Yum-Yum Good candy bars is 210, with a standard deviation of 10. If the number of calories per candy bar is normally distributed, what percent of candy bars contain more than 225 calories?

Choices:
- 66.80%
- 47.70%
- 43.30%
- 6.68%


Question: The mean daily demand for bread at a popular bakery is 2,500 loaves, with a standard deviation of 225 loaves. Every morning the bakery bakes 3,000 loaves. What is the probability that today it will run out of bread? Assume that the mean daily demand for bread at this bakery is normally distributed.

Choices:
- 0.8333
- 0.1667
- 0.9869
- 0.0132


Question: Two dice are rolled simultaneously. If both dice show 6, then the player wins $20; otherwise the player loses the game. It costs $2.00 to play the game. What is the expected gain or loss per game?

Choices:
- The player will gain about $0.55.
- The player will gain about $1.44.
- The player will lose about $0.55.
- The player will lose about $1.44.


Question: Suppose you toss a fair die three times and it comes up an even number each time. Which of the following is a true statement?

Choices:
- By the law of large numbers, the next toss is more likely to be an odd number than another even number.
- Based on the properties of conditional probability the next toss is more likely to be an even number given that three in a row have been even.
- Dice actually do have memories, and thus the number that comes up on the next toss will be influenced by the previous tosses.
- The probability that the next toss will again be even is 0.5.


Question: Taxicabs in a metropolitan area are driven an average of 75,000 miles per year with a standard deviation of 12,000 miles. What is the probability that a randomly selected cab has been driven less than 100,000 miles if it is known that it has been driven over 80,000 miles? Assume a normal distribution of miles per year among cabs.

Choices:
- 0.06
- 0.34
- 0.66
- 0.94


Question: The registrar’s office at a university has noticed that a large number of students fail to report a change of address. The registrar decides to take a random sample of 150 students from the current directory of students and determine the number of students with the correct addresses on record. He then uses this information to construct a 95 percent confidence interval. Which of the following statements must be true?

Choices:
- The true proportion of students at this university with the correct address on record is within the confidence interval constructed.
- Ninety-five percent of students at this university have the correct address on record.
- The true proportion of students at this university with the correct addresses on record is within the confidence interval 95 percent of the time.
- The sample proportion of students at this university with the correct address on record is within the confidence interval.


Question: A botanist is interested in testing H0: μ = 3.5 cm versus Ha: μ > 3.5, where μ = the mean petal length of one variety of flowers. A random sample of 50 petals gives significant results at a 5 percent level of significance. Which of the following statements about the confidence interval to estimate the mean petal length is true?

Choices:
- The specified mean length of 3.5 cm is within a 90 percent confidence interval.
- The specified mean length of 3.5 cm is not within a 90 percent confidence interval.
- The specified mean length of 3.5 cm is below the lower limit of a 90 percent confidence interval.
- The specified mean length of 3.5 cm is below the lower limit of a 95 percent confidence interval.


Question: A dentist has noticed that about two children in every seven whom he sees professionally develop cavities before they turn 10 years old. Last week he examined the teeth of five unrelated children younger than 10. Let X be the number of children who develop cavities before turning 10. Which of the following gives the probability that at least one will develop a cavity before turning 10?

Choices:
- P(X = 2, 3, 4, 5, 6, 7)
- P(X = 2 out of 7)
- P(X = 1)
- 1 – P(X = 0)


Question: Which of the following is NOT true of the χ2 probability distribution function?

Choices:
- The area under the χ2 curve is 1.
- χ2 is defined only for nonnegative values of the variable.
- For small degrees of freedom, the curve displays strong right-skewness.
- For the same α, as the number of degrees of freedom increases, the critical value for the rejection region decreases.


Question: The relation between the selling price of a car (in $1,000) and its age (in years) is estimated from a random sample of cars of a specific model. The relation is given by the following formula: Selling price = 15.9 – 0.983 (age) Which of the following can we conclude from this equation?

Choices:
- For every year the car gets older, the selling price goes down by approximately 9.83 percent.
- A new car costs on the average $9,830.
- For every year the car gets older, the selling price drops by approximately $1,590.
- For every year the car gets older, the selling price drops by approximately $983.


Question: Consider a hypothesis test with H0 : μ = 70 and Ha : μ < 70. Which of the following choices of significance level and sample size results in the greatest power of the test when μ = 65?

Choices:
- α = 0.05, n = 15
- α = 0.01, n = 15
- α = 0.05, n = 30
- α = 0.01, n = 30


Question: A farmer who raises hens for egg production wants his eggs to have a mean mass of 56 grams. He is considering the purchase of a different type of hen, so he took a random sample of 18 eggs laid by this type of hen. The distribution of the masses is symmetric and mound-shaped with a mean of 54.1 grams and no outliers. The farmer conducted a t-test to see if there is evidence that the eggs from these hens have a mean mass that is different from 56 g and got a test statistic of t= -1.973. If he uses a 5% significance level, which is the correct conclusion and reason?

Choices:
- Because tis more extreme than ±1.96, he should reject the null hypothesis. He has convincing evidence at the 5% significance level that the mean mass of eggs from these hens is different from 56 grams.
- Because tis less extreme than the critical value of t for 17 degrees of freedom, he should not reject the null hypothesis. He does not have convincing evidence at the 5% significance level that the mean mass of eggs from these hens is different from 56 grams.
- Because tis less extreme than the critical value of t for 18 degrees of freedom, he should not reject the null hypothesis. He does not have convincing evidence at the 5% significance level that the mean mass of eggs from these hens is different from 56 grams.
- Because tis more extreme than the critical value of t for 18 degrees of freedom, he should reject the null hypothesis. He has convincing evidence at the 5% significance level that the mean mass of eggs from these hens is different from 56 grams.


Question: A school committee member is lobbying for an increase in the gasoline tax to support the county school system. The local newspaper conducted a survey of county residents to assess their support for such an increase. What is the population of interest here?

Choices:
- All school-aged children
- All county residents
- All county residents with school-aged children
- All county residents with children in the county school system


Question: To survey the opinions of the students at your high school, a researcher plans to select every twenty-fifth student entering the school in the morning. Assuming there are no absences, will this result in a simple random sample of students attending your school?

Choices:
- Yes, because every student has the same chance of being selected.
- Yes, but only if there is a single entrance to the school.
- Yes, because the 24 out of every 25 students who are not selected will form a control group.
- No, because not every sample of the intended size has an equal chance of being selected.


Question: Which of the following is a true statement?

Choices:
- While properly designed experiments can strongly suggest cause-and-effect relationships, a complete census is the only way of establishing such a relationship.
- If properly designed, observational studies can establish cause-and-effect relationships just as strongly as properly designed experiments.
- Controlled experiments are often undertaken later to establish cause-and-effect relationships first suggested by observational studies.
- A useful approach to overcome bias in observational studies is to increase the sample size.


Question: An automobile service station performs oil changes and tire replacements, as well as other services. Sixty percent of its customers request an oil change, 30 percent request tire replacements, and 10 percent request both. A customer requests an oil change. What is the probability this customer does not request tire replacements?

Choices:
- 0.42
- 0.5
- 0.7
- 0.833


Question: Which of the following statements is false?

Choices:
- Like the normal distribution, the t-distributions are symmetric.
- The t-distributions are lower at the mean and higher at the tails, and so are more spread out than the normal distribution.
- The greater the df, the closer the t-distributions are to the normal distribution.
- The smaller the df, the better the 68-95-99.7 Rule works for t-models.


Question: A kidney dialysis center periodically checks a sample of its equipment and performs a major recalibration if readings are sufficiently off target. Similarly, a fabric factory periodically checks the sizes of towels coming off an assembly line and halts production if measurements are sufficiently off target. In both situations, we have the null hypothesis that the equipment is performing satisfactorily. For each situation, which is the more serious concern, a Type I or Type II error?

Choices:
- Dialysis center: Type I error, towel manufacturer: Type I error
- Dialysis center: Type I error, towel manufacturer: Type II error
- Dialysis center: Type II error, towel manufacturer: Type I error
- Dialysis center: Type II error, towel manufacturer: Type II error


Question: A company with offices in five different countries is interested in estimating the proportion of its employees in favor of banning smoking on the office premises. It is known that the views of people from different countries on issues like smoking tend to vary due to the influence of different local social structures. Which of the following is an appropriate sampling technique to use in this situation, and why?

Choices:
- Stratified sample, because the population is divided into five strata—namely, five offices in five different countries
- Cluster sample, because the population is divided into five clusters—namely, five offices in five different countries
- Simple random sample, because this is the simplest sampling method
- Simple random sample, because this is the only method that gives unbiased results


Question: Semir rolls a six-sided die every morning to determine what he will have for breakfast. If he rolls a 1 or 2, he takes time to cook himself a big breakfast. If he rolls a 3 or larger he grabs a quick lighter breakfast. When he cooks himself a big breakfast, there is a 15% chance he will be late for school. If he has a lighter breakfast, there is a 6% chance he will be late for school. What is the probability Semir will be on time for school any given day?

Choices:
- 0.09
- 0.21
- 0.8
- 0.91


Question: A teacher's union and a school district are negotiating salaries for the coming year. The teachers want more money, and the district, claiming, as always, budget constraints, wants to pay as little as possible. The district, like most, has a large number of moderately paid teachers and a few highly paid administrators. The salaries of all teachers and administrators are included in trying to figure out, on average, how much the professional staff currently earn. Which of the following would the teachers' union be most likely to quote during negotiations?

Choices:
- The mean of all the salaries.
- The mode of all the salaries.
- The standard deviation of all the salaries.
- The median of all the salaries.


Question: The Hardcore Construction Company has two offices, one in Atlanta and one in New Orleans. Fifteen engineers work in the Atlanta office, and 14 engineers work in the New Orleans office. The business manager decided to use a 2-sample t-test to compare the mean salaries of engineers in the two offices. Because there were only 15 engineers in one office and 14 engineers in the other, he used the salaries of all the engineers in the computation. Is the 2-sample t-test an appropriate inferential technique in this situation?

Choices:
- Yes, because he is comparing the means of two small groups.
- Yes. Both Atlanta and New Orleans are large cities, so the salaries are comparable.
- Yes. Because Atlanta and New Orleans are about 500 miles apart, the two groups of engineers can be assumed to be independent.
- No, because the entire population information was used from both offices. Because no samples were taken, a t-test should not be used.


Question: For the regression line, which of the following statements about residuals is true?

Choices:
- Influential scores have large residuals.
- If the linear model is good, the number of positive residuals will be the same as the number of negative residuals.
- The mean of the residuals is always zero.
- If the correlation is 0, there will be a distinct pattern in the residual plot.


Question: A reading specialist in a large public school system believes that the more time students spend reading, the better they will do in school. She plans a middle school experiment in which an SRS of 30 eighth graders will be assigned four extra hours of reading per week, an SRS of 30 seventh graders will be assigned two extra hours of reading per week, and an SRS of 30 sixth graders with no extra assigned reading will be a control group. After one school year, the mean GPAs from each group will be compared. Is this a good experimental design?

Choices:
- Yes.
- No, because while this design may point out an association between reading and GPA, it cannot establish a cause-and-effect relationship.
- No, because without blinding, there is a strong chance of a placebo effect.
- No, because grade level is a lurking variable which may well be confounded with the variables under consideration.


Question: What is a sampling distribution?

Choices:
- A distribution of all the statistics that can be found in a given sample
- A histogram, or other such visual representation, showing the distribution of a sample
- A normal distribution of some statistic
- A distribution of all the values taken by a statistic from all possible samples of a given size


Question: A farmer wants to know whether a new fertilizer has increased the mean weight of his apples. With the old fertilizer, the mean weight was 4.0 ounces per apple. The farmer decides to test H0: μ = 4.0 ounces versus Ha : μ > 4.0 ounces, at a 5 percent level of significance, where μ = the mean weight of apples using the new fertilizer. The weights of apples are approximately normally distributed. The farmer takes a random sample of 16 apples and computes a mean of 4.3 ounces and a standard deviation of 0.6 ounces. Which of the following gives the p-value for this test?

Choices:
- P(Z > 2)
- P(Z < 2)
- P(t > 2) with 15 degrees of freedom
- P(t < 2) with 15 degrees of freedom


Question: In a study on the effect of music on worker productivity, employees were told that a different genre of background music would be played each day and the corresponding production outputs noted. Every change in music resulted in an increase in production. This is an example of

Choices:
- the effect of a treatment unit.
- the placebo effect.
- the control group effect.
- sampling error.


Question: In a clinical trial, 30 sickle cell anemia patients are randomly assigned to two groups. One group receives the currently marketed medicine, and the other group receives an experimental medicine. Each week, patients report to the clinic where blood tests are conducted. The lab technician is unaware of the kind of medicine the patient is taking. This design can be described as

Choices:
- a completely randomized design, with the currently marketed medicine and the experimental medicine as two treatments
- a matched-pairs design, with the currently marketed medicine and the experimental medicine forming a pair
- a randomized block design, with the currently marketed medicine and the experimental medicine as two blocks
- a randomized block design, with the currently marketed medicine and the experimental medicine as two treatments


Question: Suppose that the weights of trucks traveling on the interstate highway system are normally distributed. If 70% of the trucks weigh more than 12,000 pounds and 80% weigh more than 10,000 pounds, what are the mean and standard deviation for the weights of trucks traveling on the interstate system?

Choices:
- μ = 14,900; σ = 6100
- μ = 15,100; σ = 6200
- μ = 15,300; σ = 6300
- μ = 15,500; σ = 6400


Question: An insurance agent is successful in selling a life insurance policy to 20 percent of the customers he contacts. He decides to construct a simulation to estimate the mean number of customers he needs to contact before being able to sell a policy. Which of the following schemes should he use to do the simulation?

Choices:
- Assign numbers 0, 1 to successfully selling a policy to a customer and numbers 2, 3, 4, 5, 6, 7, 8, 9 to failing to sell a policy to a customer.
- Assign numbers 0, 1 to successfully selling a policy to a customer and numbers 2, 3, 4 to failing to sell a policy to a customer.
- Assign number 0 to successfully selling a policy to a customer and number 1 to failing to sell a policy to a customer.
- Assign numbers 0, 1, 2, 3, 4 to successfully selling a policy to a customer and numbers 5, 6, 7, 8, 9 to failing to sell a policy to a customer.


Question: The midterm scores for a statistics course were approximately normally distributed with a mean of 52 points and a standard deviation of 4 points. The final exam scores were approximately normally distributed with a mean of 112 points and a standard deviation of 10 points. One student had a score of 58 points on the midterm. If she had the same standardized score (z-score) on the final exam, what must her score have been?

Choices:
- 15 points
- 58 points
- 118 points
- 127 points


Question: The sampling distribution of the sample mean is close to the normal distribution

Choices:
- only if both the original population has a normal distribution and n is large.
- if the standard deviation of the original population is known.
- if n is large, no matter what the distribution of the original population.
- no matter what the value of n or what the distribution of the original population.


Question: Suppose H0: p = 0.6, and the power of the test for Ha: p = 0.7 is 0.8. Which of the following is a valid conclusion?

Choices:
- The probability of committing a Type I error is 0.1.
- If Ha is true, the probability of failing to reject H0 is 0.2.
- The probability of committing a Type II error is 0.3.
- All of the above are valid conclusions.


Question: In one metropolitan region, technical writers have an annual salary that is approximately normally distributed with a mean of $55,800. The first quartile of salaries is $48,815. What is the standard deviation?

Choices:
- $6,984
- $10,356
- $10,476
- $13,968


Question: The amount of rainfall per month in a certain city is approximately normally distributed, with a mean of six inches and a standard deviation of 1.6 inches. Which of the following is the highest amount of rainfall, in inches, this city could have this month for the month to be among the 10percent driest months the city has seen?

Choices:
- 8.05
- 7.6
- 3.95
- 3.37


Question: Which of the following is most useful in establishing cause-and-effect relationships?

Choices:
- A complete census
- A least squares regression line showing high correlation
- A simple random sample (SRS)
- An experiment


Question: A sports talk show asks people to call in and give their opinion of the officiating in the local basketball team's most recent loss. What will most likely be the typical reaction?

Choices:
- They will most likely feel that the officiating could have been better, but that it was the team's poor play, not the officiating, that was primarily responsible for the loss.
- They would most likely call for the team to get some new players to replace the current ones.
- The team probably wouldn't have lost if the officials had been doing their job.
- Because the team had been foul-plagued all year, the callers would most likely support the officials.


Question: Alfred and Ben don't know each other but are each considering asking the lovely Charlene to the school prom. The probability that at least one of them will ask her is 0.72. The probability that they both ask her is 0.18. The probability that Alfred asks her is 0.6. What is the probability that Ben asks Charlene to the prom?

Choices:
- 0.78
- 0.3
- 0.24
- 0.48


Question: A random sample of 25 men and a separate random sample of 25 women are selected to answer questions about attitudes toward abortion. The answers were categorized as "pro-life" or "pro-choice." Which of the following is the proper null hypothesis for this situation?

Choices:
- The variables "gender" and "attitude toward abortion" are related.
- The proportion of "pro-life" men is the same as the proportion of "pro-life" women.
- The proportion of "pro-life" men is related to the proportion of "pro-life" women.
- The proportion of "pro-choice" men is the same as the proportion of "pro-life" women.


Question: A 2008 survey of 500 households concluded that 82% of the population uses grocery coupons. Which of the following best describes what is meant by the poll having a margin of error of 3%?

Choices:
- Three percent of those surveyed refused to participate in the poll.
- It would not be unexpected for 3% of the population to begin using coupons or stop using coupons.
- Between 395 and 425 of the 500 households surveyed responded that they used grocery coupons.
- It is likely that between 79% and 85% of the population use grocery coupons.


Question: A hypothesis test is set up so that P(rejecting H0 when H0 is true) = 0.05 and P(failing to reject H0 when H0 is false) = 0.26. What is the power of the test?

Choices:
- 0.26
- 0.05
- 0.95
- 0.74


Question: For a class project, Charlotte recorded the heights of all 28 students in her class and calculated several statistics. She then realized she made an error recording the height of the tallest person in the class. She correctly had him listed as the tallest, but needed to add two inches to his recorded height to correct it. Which of these measures of spread must remain unchanged?

Choices:
- Mean absolute deviation
- Standard deviation
- Variance
- Interquartile range


Question: The main purpose of blocking in an experiment is to:

Choices:
- reduce bias.
- reduce confounding.
- reduce variation within treatments.
- reduce variation between treatments.


Question: A manufacturer of motor oil is interested in testing the effects of a newly developed additive on the lifespan of an engine. Twenty-five different engine types are selected at random and each one is tested using oil with the additive and oil without the additive. What type of analysis will yield the most useful information?

Choices:
- Matched pairs comparison of population proportions
- Matched pairs comparison of population means
- Independent samples comparison of population proportions
- Independent samples comparison of population means


Question: To determine the average cost of running for a congressional seat, a simple random sample of 50 politicians is chosen and the politicians' records examined. The cost figures show a mean of $125,000 with a standard deviation of $32,000. Which of the following is the best interpretation of a 90% confidence interval estimate for the average cost of running for office?

Choices:
- 90% of politicians running for a congressional seat spend between $117,500 and $132,500.
- 90% of politicians running for a congressional seat spend a mean dollar amount that is between $117,500 and $132,500.
- We are 90% confident that politicians running for a congressional seat spend between $117,500 and $132,500.
- We are 90% confident that politicians running for a congressional seat spend a mean dollar amount between $117,500 and $132,500.


Question: A filling machine puts an average of four ounces of coffee in jars, with a standard deviation of 0.25 ounces. Forty jars filled by this machine are selected at random. What is the probability that the mean amount per jar filled in the sampled jars is less than 3.9 ounces?

Choices:
- 0.0057
- 0.0225
- 0.025
- 0.05


Question: A town has one high school, which buses students from urban, suburban, and rural communities. Which of the following samples is recommended in studying attitudes toward tracking of students in honors, regular, and below-grade classes?

Choices:
- Convenience sample
- Simple random sample (SRS)
- Stratified sample
- Systematic sample


Question: A shipment of resistors have an average resistance of 200 ohms with a standard deviation of 5 ohms, and the resistances are normally distributed. Suppose a randomly chosen resistor has a resistance under 194 ohms. What is the probability that its resistance is greater than 188 ohms?

Choices:
- 0.07
- 0.12
- 0.50
- 0.93


Question: A major polling organization wants to predict the outcome of an upcoming national election (in terms of the proportion of voters who will vote for each candidate). They intend to use a 95% confidence interval with margin of error of no more than 2.5%. What is the minimum sample size needed to accomplish this goal?

Choices:
- 1536
- 39
- 1537
- 40


Question: Given that the sample has a standard deviation of zero, which of the following is a true statement?

Choices:
- The standard deviation of the population is also zero.
- The sample mean and sample median are equal.
- The sample may have outliers.
- The population has a symmetric distribution.


Question: The number of customers served per day by a large department store is normally distributed, with a mean of 3,250 customers and a standard deviation of 320. Find the range of customers served on the middle 50 percent of days.

Choices:
- (3,034, 3,466)
- (2,930, 3,570)
- (2,610, 3,890)
- (2,450, 4,050)


Question: Suppose that 54% of the graduates from your high school go on to 4-year colleges, 20% go on to 2-year colleges, 19% find employment, and the remaining 7% search for a job. If a randomly selected student is not going on to a 2-year college, what is the probability she will be going on to a 4-year college?

Choices:
- 0.460
- 0.540
- 0.630
- 0.675


Question: The Department of Health plans to test the lead level in a specific park. Because a high lead level is harmful to children, the park will be closed if the lead level exceeds the allowed limit. The department randomly selects several locations in the park, gets soil samples from those locations, and tests the samples for their lead levels. Which of the following decisions would result from the type I error?

Choices:
- Closing the park when the lead levels are within the allowed limit
- Keeping the park open when the lead levels are in excess of the allowed limit
- Closing the park when the lead levels are in excess of the allowed limit
- Keeping the park open when the lead levels are within the allowed limit


Question: For a class project, a student wants to see if boys and girls at their large high school differ in the number of contacts they have stored in their phone. The student conducts a survey of 50 randomly sampled boys and 40 randomly selected girls, and asks them to report the number of contacts. Which of the following is true about this situation?

Choices:
- Because the population standard deviations are not known and conditions are met, the student shoulduse a two-sample t-test.
- Because the sample sizes are different, the student should notuse a two-sample t-test.
- Because the sample sizes are both greater than 30, the student should notuse a two-sample t-test.
- Because the shape of the population distribution is not known, the student should notuse a two-sample t-test.


Question: The probability is 0.2 that a value selected at random from a normal distribution with mean 600 and standard deviation 15 will be above what number?

Choices:
- 0.84
- 603.8
- 612.6
- 587.4


Question: In a group of 10 scores, the largest score is increased by 40 points. What will happen to the mean?

Choices:
- It will remain the same.
- It will increase by 4 points.
- It will increase by 10 points.
- It will increase by 40 points.


Question: The distribution of salaries of a county school system with 4,752 employees is known to be right skewed, with the superintendent’s salary an outlier on the higher side. A random sample of 20 employees was taken and their salaries recorded. A 95 percent t-confidence interval for the mean salary of the county school system employees is ($15,360, $32,470). The t-confidence interval is not appropriate in this situation because

Choices:
- the sample size is too small compared to the number of employees in the system to give a fair representation
- the skewed salary distribution tells us that assumption of normality of the sampled population will not be satisfied
- the population standard deviation of the salaries of employees of this county school system is not known
- the teacher salaries are not negotiable, but the superintendent’s salary is negotiable, so the superintendent’s salary should be excluded from the population sampled


Question: Assume that the masses of chicken eggs are normally distributed with a mean of 45 g and a standard deviation of 4 g. What mass of egg would be the 25th percentile of the masses of all the eggs?

Choices:
- 42.2 g
- 42.3 g
- 42.4 g
- 42.5 g


Question: A recent poll reported that 43% of Americans approve of the job the president is doing, with a margin of sampling error of ±3.2% at a 95% level of confidence. Which of these correctly interprets that margin of error?

Choices:
- There is a 3.2% percent chance that the proportion of all Americans who approve of the job the president is doing is not 43%.
- There is a 95% chance that the proportion of all Americans who approve of the job the president is doing is 43%.
- About 95% of polls conducted in this way will find that between 39.8% and 46.2% of those sampled approve of the job the president is doing.
- About 95% of polls conducted in this way will give a sample proportion within 3.2 percentage points of the actual proportion of all Americans who approve of the job the president is doing.


Question: What is the probability of a Type II error when a hypothesis test is being conducted at the 10% significance level (α = 0.10)?

Choices:
- 0.05
- 0.10
- 0.90
- There is insufficient information to answer this question.


Question: In comparing the life expectancies of two models of refrigerators, the average years before complete breakdown of 10 model A refrigerators is compared with that of 15 model B refrigerators. The 90% confidence interval estimate of the difference is (6, 12). Which of the following is the most reasonable conclusion?

Choices:
- The mean life expectancy of one model is twice that of the other.
- The mean life expectancy of one model is 6 years, while the mean life expectancy of the other is 12 years.
- The probability that the life expectancies are different is 0.90.
- We should be 90% confident that the difference in life expectancies is between 6 and 12 years.


Question: A medicine is known to produce side effects in one in five patients taking it. Suppose a doctor prescribes the medicine to four unrelated patients. What is the probability that none of the patients will develop side effects?

Choices:
- 0.8
- 0.4096
- 0.25
- 0.2


Question: Which of the following is notan advantage of stratified random sampling over simple random sampling?

Choices:
- When done correctly, a stratified random sample is less biased than a simple random sample.
- When done correctly, a stratified random sampling process has less variability from sample to sample than a simple random sample.
- When done correctly, a stratified random sample can provide, with a smaller sample size, an estimate that is just as reliable as that of a simple random sample with a larger sample size.
- A stratified random sample provides information about each stratum in the population as well as an estimate for the population as a whole, and a simple random sample does not.


Question: In the casino game of roulette, there are 38 slots for a ball to drop into when it is rolled around the rim of a revolving wheel: 18 red, 18 black, and 2 green. What is the probability that the first time a ball drops into the red slot is on the 8th trial (in other words, suppose you are betting on red every time-what is the probability of losing 7 straight times before you win the first time)?

Choices:
- 0.0278
- 0.0112
- 0.0053
- 0.0101


Question: A talk show host recently reported that in response to his on-air question, 82% of the more than 2500 e-mail messages received through his publicized address supported the death penalty for anyone convicted of selling drugs to children. What does this show?

Choices:
- The survey is meaningless because of voluntary response bias.
- No meaningful conclusion is possible without knowing something more about the characteristics of his listeners.
- The survey would have been more meaningful if he had picked a random sample of the 2500 listeners who responded.
- The survey would have been more meaningful if he had used a control group.


Question: To determine the average number of children living in single-family homes, a researcher picks a simple random sample of 50 such homes. However, even after one follow-up visit the interviewer is unable to make contact with anyone in 8 of these homes. Concerned about nonresponse bias, the researcher picks another simple random sample and instructs the interviewer to keep trying until contact is made with someone in a total of 50 homes. The average number of children is determined to be 1.73. Is this estimate probably too low or too high?

Choices:
- Too low, because of undercoverage bias.
- Too low, because convenience samples overestimate average results.
- Too high, because of undercoverage bias.
- Too high, because convenience samples overestimate average results.


Question: If all the values of a data set are the same, all of the following must equal zero except for which one?

Choices:
- Mean
- Standard deviation
- Variance
- Range


Question: A university sent out a survey to a random sample of 120 recent graduates to see how those graduates feel about the education they received. Thirty-two of the graduates did not respond to the survey. Which of these would be the best way to proceed?

Choices:
- Use the 88 who did respond, using 88 as the sample size in the analysis.
- Use the 88 who did respond, using 120 as the sample size in the analysis.
- Attempt to contact the 32 who did not respond and get the information from them.
- Select 32 more graduates at random and use them to replace the nonresponders.


Question: Given the probabilities P(A) = 0.3 and P(B) = 0.2, what is the probability of the union P(A ∪ B) if A and B are mutually exclusive? If A and B are independent? If B is a subset of A?

Choices:
- 0.44, 0.5, 0.2
- .44, 0.5, 0.3
- .5, 0.44, 0.2
- .5, 0.44, 0.3


Question: Which of the following is true about any discrete probability distribution of a random variable X?

Choices:
- The expected value of X = np.
- The sum of all possible values of X is equal to one.
- The probabilities of all possible values of X must add up to one.
- The probability distribution is bell-shaped and symmetric.


Question: Which among the following would result in the narrowest confidence interval?

Choices:
- Small sample size and 95% confidence
- Small sample size and 99% confidence
- Large sample size and 95% confidence
- Large sample size and 99% confidence


Question: The correlation between height in inches and weight in pounds for a particular class is 0.65. If the heights are converted from inches to centimeters, what will the correlation be? (1 in. = 2.54 cm)

Choices:
- -0.65
- -0.26
- 0.1
- 0.65


Question: The number of days it takes to build a new house has a variance of 386. A sample of 40 new homes shows an average building time of 83 days. With what confidence can we assert that the average building time for a new house is between 80 and 90 days?

Choices:
- 15.4%
- 17.8%
- 20.0%
- 82.1%


Question: A significance test of the hypothesis H0: p= 0.3 against the alternative HA: p> 0.3 found a value of = 0.35 for a random sample of size 95. What is the P-value of this test?

Choices:
- 1.06
- 0.1446
- 0.2275
- 0.8554


Question: Two events A and B each have a nonzero probability. If A and B are independent, which of the following statements is true?

Choices:
- P(A and B) = P(A) · P(B)
- A and B may or may not be mutually exclusive.
- A and B must be mutually exclusive.
- P(A| B) = P(B| A)


Question: A teacher believes that giving her students a practice quiz every week will motivate them to study harder, leading to a greater overall understanding of the course material. She tries this technique for a year, and everyone in the class achieves a grade of at least C. Is this an experiment or an observational study?

Choices:
- An experiment, but with no reasonable conclusion possible about cause and effect
- An experiment, thus making cause and effect a reasonable conclusion
- An observational study, because there was no use of a control group
- An observational study, but a poorly designed one because randomization was not used


Question: Which of these is the best description of a P-value?

Choices:
- The probability of making a Type I error.
- The probability of making a Type II error.
- The probability of rejecting the null hypothesis if it is, in fact, false.
- The probability of getting a test statistic at least as extreme as the observed test statistic, if the null hypothesis is true.


Question: The financial aid office at a state university conducts a study to determine the total student costs per semester. All students are charged $4500 for tuition. The mean cost for books is $350 with a standard deviation of $65. The mean outlay for room and board is $2800 with a standard deviation of $380. The mean personal expenditure is $675 with a standard deviation of $125. Assuming independence among categories, what is the standard deviation of the total student costs?

Choices:
- $24
- $91
- $190
- $405


Question: Self-efficacy (the belief that one has control over one's situation) as it related to job satisfaction was studied. When a group of teachers rated their ability to control their situation and their satisfaction with their job, the two variables had a correlation of 0.30. Which statement follows from this correlation?

Choices:
- If you want teachers to be happy with their job, give them more control over their situation.
- If you want teachers to take more control over their situation, make them happier at their jobs.
- Teachers in the study who were more satisfied with their job were less confident in their ability to control their situation.
- 9% of the variability in job satisfaction can be explained by the linear model with self-efficacy as a predictor.


Question: Suppose X and Y are random variables with E(X) = 312, var(X) = 6, E(X) = 307, and var(Y) = 8. What are the expected value and variance of the random variable X + Y?

Choices:
- E(X + Y) = 619, var(X + Y) = 7
- E(X + Y) = 619, var(X + Y) = 10
- E(X + Y) = 619, var(X + Y) = 14
- There is insufficient information to answer this question.


Question: Consider the two sets X = {10, 30, 45, 50, 55, 70, 90} and Y = {10, 30, 35, 50, 65, 70, 90}. Which of the following is false?

Choices:
- The sets have identical medians.
- The sets have identical means.
- The sets have identical ranges.
- None of the above are false.


Question: Which of the following is a true statement?

Choices:
- In a well-designed, well-conducted sample survey, sampling error is effectively eliminated.
- In a well-designed observational study, responses are influenced through an orderly, carefully planned procedure during the collection of data.
- In a well-designed experiment, the treatments are carefully planned to result in responses that are as similar as possible.
- None of the above is a true statement.


Question: A researcher is hoping to find a predictive linear relationship between the explanatory and response variables in her study. Accordingly, as part of her analysis she plans to generate a 95% confidence interval for the slope of the regression line for the two variables. The interval is determined to be (0.45, 0.80). Which of the following is (are) true? (Assume conditions for inference are met.) I. She has good evidence of a linear relationship between the variables. II. It is likely that there is a non-zero correlation (r) between the two variables. III. It is likely that the true slope of the regression line is 0.

Choices:
- I and II only
- I and III only
- II and III only
- I only


Question: A student organization at a university is interested in estimating the proportion of students in favor of showing movies biweekly instead of monthly. How many students should be sampled to get a 90 percent confidence interval with a width of at most 0.08?

Choices:
- 27
- 64
- 106
- 423


Question: A correlation of 0.6 indicates that the percentage of variation in y that is explained by the variation in x is how many times the percentage indicated by a correlation of 0.3?

Choices:
- 2
- 3
- 4
- 6


Question: For which of the following is it appropriate to use a census?

Choices:
- A 95% confidence interval of mean height of teachers in a small town.
- A 95% confidence interval of the proportion of students in a small town who are taking some AP class.
- A two-tailed hypothesis test where the null hypothesis was that the mean expenditure on entertainment by male students at a high school is the same as that of female students.
- None of the above.


Question: Which of the following is the best description of the power of a significance test?

Choices:
- The probability that the null hypothesis is true.
- The probability of getting a Type I error.
- The probability of getting a Type II error.
- The probability of rejecting the null hypothesis if it is, in fact, false.


Question: A drug company will conduct a randomized controlled study on the effectiveness of a new heart disease medication called Heartaid. Heartaid is more expensive than the currently used medication. The analysis will include a significance test with H0: Heartaid and the current medication are equally effective at preventing heart disease and HA: Heartaid is more effective than the current medication at preventing heart disease. Which of these would be a potential consequence of a Type II error?

Choices:
- Patients will spend more money on Heartaid, even though it is actually not any more effective than the current medication.
- Doctors will begin to prescribe Heartaid to patients, even though it is actually not any more effective than the current medication.
- Patients will continue to use the current medication, even though Heartaid is actually more effective.
- Researchers will calculate the wrong P-value, making their advice to doctors invalid.


Question: Two classes take the same exam. Suppose a certain score is at the 40th percentile for the first class and at the 80th percentile for the second class. Which of the following is the most reasonable conclusion?

Choices:
- Students in the first class generally scored higher than students in the second class.
- Students in the second class generally scored higher than students in the first class.
- A score at the 20th percentile for the first class is at the 40th percentile for the second class.
- A score at the 50th percentile for the first class is at the 90th percentile for the second class.


Question: The mean thrust of a certain model jet engine is 9500 pounds. Concerned that a production process change might have lowered the thrust, an inspector tests a sample of units, calculating a mean of 9350 pounds with a z-score of -2.46 and a P-value of 0.0069. Which of the following is the most reasonable conclusion?

Choices:
- 99.31% of the engines produced under the new process will have a thrust under 9350 pounds.
- 99.31% of the engines produced under the new process will have a thrust under 9500 pounds.
- 0.69% of the time an engine produced under the new process will have a thrust over 9500 pounds.
- There is evidence to conclude that the new process is producing engines with a mean thrust under 9500 pounds.


Question: When the point (15,2) is included, the slope of regression line (y= a+ bx) is b= -0.54. The correlation is r= -0.82. When the point is removed, the new slope is -1.04 and the new correlation coefficient is -0.95. What name is given to a point whose removal has this kind of effect on statistical calculations?

Choices:
- Outlier
- Statistically significant point
- Point of discontinuity
- Influential point


Question: What is true for a type-Ia ("type one-a") supernova?

Choices:
- This type occurs in binary systems.
- This type occurs in young galaxies.
- This type produces gamma-ray bursts.
- This type produces high amounts of X-rays.


Question: If you know both the actual brightness of an object and its apparent brightness from your location then with no other information you can estimate:

Choices:
- Its speed relative to you
- Its composition
- Its size
- Its distance from you


Question: Why is the sky blue?

Choices:
- Because the molecules that compose the Earth's atmosphere have a blue-ish color.
- Because the sky reflects the color of the Earth's oceans.
- Because the atmosphere preferentially scatters short wavelengths.
- Because the Earth's atmosphere preferentially absorbs all other colors.


Question: You’ve made a scientific theory that there is an attractive force between all objects. When will your theory be proven to be correct?

Choices:
- The first time you drop a bowling ball and it falls to the ground proving your hypothesis.
- After you’ve repeated your experiment many times.
- You can never prove your theory to be correct only “yet to be proven wrong”.
- When you and many others have tested the hypothesis.


Question: Which of the following is/are true?

Choices:
- Titan is the only outer solar system moon with a thick atmosphere
- Titan is the only outer solar system moon with evidence for recent geologic activity
- Titan's atmosphere is composed mostly of hydrocarbons
- A and D


Question: A comet of mass m impacts the earth (mass M radius R) at the minimum impact speed. What is the expression for the total energy released in the impact?

Choices:
- m*v
- 0.5*m/(R^3)
- 0.5*m*(2GM/R)
- 0.6*G(M^2)/R


Question: Some of Mars'water is frozen in the soil and the ice caps and some was lost due to solar wind stripping but much of the original water is thought to have been lost through another mechanism. What happened to this "lost"water?

Choices:
- it was stripped away by the magnetic field when it rapidly decreased in strength
- it was broken into hydrogen and oxygen by ultraviolet light and the hydrogen was lost through thermal escape
- it was consumed by a civilization of thirsty Martians
- it was vaporized during a period of intense volcanism and was lost to space through thermal escape


Question: Most rocks on the Moon's surface are older than those on the Earth's surface. The best evidence for this is:

Choices:
- Lunar rocks are composed of fragments pulverized by many impacts.
- Radioactive dating of lunar samples shows that they are older.
- The Moon's surface is more heavily eroded than the Earth's surface.
- The Moon's surface has more impact craters than the Earth's surface.


Question: What is the second most common element in the solar system?

Choices:
- Iron
- Hydrogen
- Methane
- Helium


Question: What is the source of the material that causes meteor showers?

Choices:
- Near-Earth asteroids gradually disintegrate and spread out along their orbital path. When the Earth passes through the orbit of an asteroid we are bombarded by sand-sized particles which cause a meteor shower.
- Near-Earth asteroids disintegrate as they enter Earth's atmosphere creating hundreds of bright meteors that appear to radiate from a single location in the sky.
- The nuclei of comets disintigrate as they enter Earth's atmosphere creating hundreds of bright meteors that appear to radiate from a central location in the sky.
- The nuclei of comets gradually disintegrate and spread out along the comet's orbital path. When the Earth passes through the orbit of a comet we are bombarded by sand-sized particles which cause a meteor shower.


Question: Why does the plasma (ion) tail of a comet always point away from the Sun?

Choices:
- Radiation pressure from the Sun's light pushes the ions away.
- The conservation of the angular momentum in the tail keeps it always pointing away from the Sun.
- The ions are following Keplerian orbits that lead away from the Sun.
- The solar wind electromagnetically "blows" the ions directly away from the Sun.


Question: How did Eratosthenes estimate the size of Earth in 240 B.C.?

Choices:
- By observing the duration of a solar eclipse.
- By measuring the size of Earth's shadow on the Moon in a lunar eclipse.
- By comparing the maximum altitude of the Sun in two cities at different latitudes at the same time on the same day.
- By sending fleets of ships around Earth.


Question: The Large Magellanic Cloud is ...

Choices:
- a dwarf galaxy orbiting the Milky Way.
- the closest planetary nebula to the Earth.
- a bright star cluster discovered by Magellan.
- the outer arm of the Milky Way named after Magellan.


Question: Why do we look for water-ice in craters at Mercury's pole?

Choices:
- Actually water-ice is all over Mercury and not just at the poles.
- The pole is the only place fortunate enough to have had comet impacts
- Radar from the earth can only see Mercury's poles.
- These craters contain the only permanently shadowed regions on Mercury


Question: The Milky Way is part of a giant supercluster with a diameter of 160 Mpc. What is the name of this supercluster?

Choices:
- Virgo
- Laniakea
- Sculptor
- Boötes


Question: On which planet in our solar system can you find the Great Red Spot?

Choices:
- Venus
- Mars
- Jupiter
- Saturn


Question: Why does Earth have the strongest magnetic field among the terrestrial worlds?

Choices:
- It is by far the largest terrestrial world.
- It is the most volcanically active world.
- It is the only one that has both a partially molten metallic core and reasonably rapid rotation.
- It rotates much faster than any other terrestrial world.


Question: Which of the following is not true?

Choices:
- The Earth and Venus are in a 1:1 orbital resonance (for every 1 Earth orbit there is exactly 1 Venus orbit)
- Neptune and Pluto are in a 3:2 orbital resonance (for every 3 Neptune orbits there are exactly 2 Pluto orbits)
- The Kirkwood Gaps in the asteroid belt are due to resonances with Jupiter
- Neptune and Pluto won't collide because of their orbital resonance


Question: Which of the following is/are common feature(s) of all fresh (i.e. not eroded) impact craters formed on solid surfaces:

Choices:
- ejecta
- raised rims
- central peaks
- A and B only


Question: From laboratory measurements we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nm. What can we conclude?

Choices:
- The star is getting hotter.
- The star is getting colder.
- The star is moving toward us.
- The star is moving away from us.


Question: The lithosphere of a planet is the layer that consists of

Choices:
- the softer rocky material of the mantle.
- the lava that comes out of volcanoes.
- material between the crust and the mantle.
- the rigid rocky material of the crust and uppermost portion of the mantle.


Question: What is the Cassini division of Saturn's rings?

Choices:
- a dark ring visible from Earth composed of dark dusty particles
- the most opaque ring of Saturn made of highly reflective ice particles
- the widest ring of Saturn located between two large ring gaps
- a large gap visible from Earth produced by an orbital resonance with the moon Mimas


Question: Which of the following statements about sidereal and solar days is not true?

Choices:
- The time it takes for the Sun to make one circuit of our sky is one solar day.
- A solar day is 4 minutes longer than a sidereal day.
- A solar day represents more than 360° of rotation for the earth.
- The time it takes for the Moon to make one circuit of our sky is one solar day.


Question: Meteorites with high metal content probably are

Choices:
- pieces of comets rather than of asteroids.
- chunks of large differentiated asteroids that were shattered by collisions.
- chunks of rock chipped off the planet Mars.
- leftover chunks of rock from the earliest period in the formation of the solar system.


Question: Most people use C°(degree Celsius) to measure everyday temperatures. Astronomers prefer to use K (Kelvin) to measure temperatures. Approximately how many Kelvin are 25 C°?

Choices:
- 200 Kelvin
- 250 Kelvin
- 300 Kelvin
- 350 Kelvin


Question: The four big moons of Jupiter are Callisto Europa Ganymede and Io. Which one of them has the smallest distance to Jupiter?

Choices:
- Callisto
- Europa
- Ganymede
- Io


Question: Why are the season's in Mars' southern hemisphere so extreme?

Choices:
- because Mars is farther from the sun than the Earth
- because Mars has more carbon dioxide in its atmosphere than the Earth
- because Mars has a more eccentric orbit than the Earth
- because Mars' axis is more tilted than the Earth's


Question: What Mars mission will be landing on May 25 2008 and will dig a trench into (hopefully) ice-rich soil?

Choices:
- ExoMars
- Mars Exploration Rovers
- Mars Science Laboratory
- Phoenix Mars Lander


Question: What is the significance of the 1:2:4 resonance in the Jupiter's moons system?

Choices:
- The resonance pulls Io in different directions and generates heat.
- It makes the orbit of Io slightly elliptical.
- It creates a gap with no asteriods between the orbits.
- It prevents formation of the ring material into other moons.


Question: The terrestrial planet cores contain mostly metal because

Choices:
- the entire planets are made mostly of metal.
- metals condensed first in the solar nebula and the rocks then accreted around them.
- metals sank to the center during a time when the interiors were molten throughout.
- radioactivity created metals in the core from the decay of uranium.


Question: Why are the inner planets made of denser materials than the outer planets?

Choices:
- In the beginning when the protoplanetary disk was spinning faster centrifugal forces flung the lighter materials toward the outer parts of the solar nebula.
- In the inner part of the nebula only metals and rocks were able to condense because of the high temperatures whereas hydrogen compounds although more abundant were only able to condense in the cooler outer regions.
- Denser materials were heavier and sank to the center of the nebula.
- When the solar nebula formed a disk materials naturally segregated into bands and in our particular solar system the denser materials settled nearer the Sun while lighter materials are found in the outer part.


Question: What do meteorites reveal about the solar system?

Choices:
- They reveal that the early solar system consisted mostly of hydrogen and helium gas.
- They reveal that meteorites are much older than the comets and planets.
- They reveal that the age of the solar system is approximately 4.6 billion years.
- They reveal that the solar system once contained 10 planets.


Question: Venus shows evidence of which of the following surface processes?

Choices:
- Impacts
- Erosion
- Volcanism
- A B and C


Question: Planetary rings are

Choices:
- known to exist for all of the jovian planets.
- composed of a large number of individual particles that orbit their planet in accord with Kepler's third law.
- nearer to their planet than any of the planet's large moons.
- all of the above


Question: Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes?

Choices:
- You will not be able to see these two stars at all.
- You will see two distinct stars.
- The two stars will look like a single point of light.
- The two stars will appear to be touching looking rather like a small dumbbell.


Question: What is not true of Jupiter's magnetic field?

Choices:
- it is about 20000 times stronger than Earth's magnetic field
- it traps charged particles from Io's volcanoes in a "plasma torus" around the planet
- it causes spectacular auroral displays at Jupiter's north and south poles
- it switches polarity every 11 years


Question: What does the astronomical term ecliptic describe?

Choices:
- The path of the Sun in the sky throughout a year.
- The axial tilt of the Earth throughout a year.
- The movement of the stars due to Earth’s rotation.
- The central line through the axis of rotation.


Question: The so-called dark energy is a model to explain ...

Choices:
- the radiation of black holes.
- the mass distribution of galaxies.
- the acceleration of the universe.
- the microwave background of the universe.


Question: How do scientists know that the majority of meteorites come from the asteroid belt?

Choices:
- Bubbles of gas trapped in the crystals within meteorites are identical to the gases trapped in asteroids.
- The spectra of some meteorites are similar to the spectra of asteroids in the asteroid belt.
- Collisions are common in the asteroid belt and we can track the fragments from their source asteroid to the Earth where they become meteorites.
- The asteroid belt is the only possible source of meteorites therefore they must originate there.


Question: Jupiter and the other jovian planets are sometimes called "gas giants." In what sense is this term misleading?

Choices:
- The materials they are made of are not normally gaseous in everyday experience.
- They actually contain a significant fraction of non-gaseous matter.
- The materials that make up these planets are primarily in the form of a plasma not a gas.
- Actually it's a great description because these worlds are big and gaseous throughout.


Question: Which of the following is not one of nor follows directly from Kepler's laws?

Choices:
- As a planet moves around its orbit it sweeps out equal areas in equal times.
- The orbit of each planet about the Sun is an ellipse with the Sun at one focus.
- The force of attraction between any two objects decreases with the square of the distance between their centers.
- A planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun.


Question: The name of the black hole in the center of our Milky Way is ...

Choices:
- Altair A*
- Alsephina A*
- Fomalhaut A*
- Sagittarius A*


Question: Why is Saturn almost as big as Jupiter despite its smaller mass?

Choices:
- Jupiter's greater mass compresses it more thus increasing its density.
- Saturn has a larger proportion of hydrogen and helium than Jupiter and is therefore less dense.
- Jupiter's strong magnetic field constrains its size.
- Saturn is further from the Sun thus cooler and therefore less compact.


Question: Which of these has NOT been one of the main hypotheses considered for the origin of the Moon?

Choices:
- The Moon split from the Earth due to tidal forces.
- The Moon was captured into Earth orbit.
- The Earth and Moon co-accreted in the solar nebula.
- Earth was rotating so rapidly that the Moon split from it.


Question: We were first able to accurately measure the diameter of Pluto from:

Choices:
- a New Horizons flyby in the 1990s
- Hubble Space Telescope images that resolved Pluto's disk
- brightness measurements made during mutual eclipses of Pluto and Charon
- radar observations made by the Arecibo telescope


Question: According to the Solar Nebular theory what are asteroids and comets?

Choices:
- They are the shattered remains of collisions between planets.
- They are chunks of rock or ice that condensed long after the planets and moons had formed.
- They are chunks of rock or ice that were expelled from planets by volcanoes.
- They are leftover planetesimals that never accreted into planets.


Question: How do we know how old the Earth is?

Choices:
- From the layering of materials within the Earth.
- From fossils of ancient life.
- From the cratering history of Earth’s surface.
- From radioactive dating of rocks and meteorites.


Question: Life on Earth originated from

Choices:
- We don't know for sure.
- aliens (panspermia).
- comets.
- the Earth's oceans.


Question: By locating the north celestial pole (NCP) in the sky how can you determine your latitude?

Choices:
- The azimuth of the NCP is the angular distance from the North Pole.
- The azimuth of the NCP is the same as your latitude.
- The altitude of the NCP is the same as your latitude.
- The altitude of the NCP is your angular distance from the North Pole.


Question: How does the greenhouse effect work?

Choices:
- Ozone transmits visible light allowing it to heat the surface but then absorbs most of the infrared heat trapping the heat near the surface.
- Greenhouse gases transmit visible light allowing it to heat the surface but then absorb infrared light from Earth trapping the heat near the surface.
- Greenhouse gases absorb infrared light from the Sun which then heats the atmosphere and the surface.
- Greenhouse gases absorb X-rays and ultraviolet light from the Sun which then heat the atmosphere and the surface.


Question: Why is Saturn almost as big as Jupiter despite its smaller mass?

Choices:
- Jupiter's greater mass compresses it more thus increasing its density.
- Saturn has a larger proportion of hydrogen and helium than Jupiter and is therefore less dense.
- Saturn is further from the Sun thus cooler and therefore less compact.
- Saturn's rings make the planet look bigger.


Question: Calculate the ratio of the solar radiation flux on Mercury's surface for perihelion (0.304 AU) versus aphelion (0.456 AU).

Choices:
- 4:1
- 1:2
- 6:5
- 9:4


Question: The terrestrial planet cores contain mostly metal because

Choices:
- the entire planets are made mostly of metal.
- radioactivity created metals in the core from the decay of uranium.
- metals condensed first in the solar nebula and the rocks then accreted around them.
- metals differentiated to the center during a time when the interiors were molten throughout.


Question: Which of the following countries has sent landers to Venus?

Choices:
- The U.S.S.R.
- The U.S.
- France
- A and B


Question: Which of the following is/are NOT caused by orbital resonance?

Choices:
- 2:3 periodic ratio of Neptune:Pluto
- Kirkwood Gaps.
- Gaps in Saturn's rings.
- Breaking of small Jovian moons to form ring materials.


Question: Why is it thought that the climate on Mars changed when the planet lost its strong magnetic field?

Choices:
- without a strong magnetic field the ozone layer was destroyed by the solar wind which stopped the greenhouse effect and cooled Mars down.
- without a strong magnetic field which enhances the greenhouse effect Mars cooled down.
- without a strong magnetic field the solar wind stripped away most of the atmosphere significantly reducing the greenhouse effect and cooling Mars down
- without a strong magnetic field the planet recieves fewer charged particles from the solar wind and therefore is not heated as much


Question: Which of the following moons is NOT one of the Galilean moons?

Choices:
- Ganymede
- Callisto
- Europa
- Dione


Question: Planet X orbits its sun once every 100 Earth days and rotates in the prograde direction around its axis with a sidereal day of 100 Earth days. How long is a solar day on Planet X?

Choices:
- About 10 earth days
- About 100 earth days
- About 200 earth days
- There is no solar day Planet X is tidally locked


Question: When traveling north from the United States into Canada you’ll see the North Star (Polaris) getting _________.

Choices:
- Brighter
- Dimmer
- Higher in the sky
- Lower in the sky


Question: When will the next major impact occur on Earth?

Choices:
- Hundreds of millennia in the future.
- Major impacts can no longer occur since the period of heavy bombardment is over.
- Hundreds of millennia after the last major impact.
- Could be any time. The probability of impact is the same next year as it is for any later year.


Question: What about asteroids makes them stand out in sky surveys searching for them?

Choices:
- Asteroids emit pulsed radiation
- Asteroids emit a lot of their own radiation
- They reflect enough of the sun's light to make them brighter than most background stars
- Asteroids have substantial motion relative to the background stars


Question: Why did the solar nebula heat up as it collapsed?

Choices:
- Collisions among planetesimals generated friction and heat.
- Radiation from other nearby stars that had formed earlier heated the nebula.
- The shock wave from a nearby supernova heated the gas.
- As the cloud shrank its gravitational potential energy was converted to kinetic energy and then into thermal energy.


Question: You observe the visible spectrum of a star viewed through a cloud of cool hydrogen gas.

Choices:
- You see only the star’s blackbody spectrum.
- You see the star’s blackbody spectrum with absorption lines due to hydrogen.
- You see only emission lines characteristic of hydrogen.
- You see only emission lines characteristic of the star’s composition.


Question: Which of the following most likely explains why Venus does not have a strong magnetic field?

Choices:
- Its rotation is too slow.
- It has too thick an atmosphere.
- It is too large.
- It does not have a metallic core.


Question: Which of the following characteristics would not necessarily suggest that a rock we found is a meteorite.

Choices:
- It has a fusion crust
- It contains solidified spherical droplets
- It is highly processed
- It has different elemental composition than earth


Question: Which is not a similarity between Saturn and Jupiter's atmospheres?

Choices:
- a composition dominated by hydrogen and helium
- the presence of belts zones and storms
- an equatorial wind speed of more than 900 miles per hour
- significant "shear" between bands of circulation at different latitudes


Question: Jupiter's orbital distance is roughly 5 AU. How many times brighter would the Sun have to be for Europa to receive the same solar flux that we currently receive on Earth (1380W/m2)?

Choices:
- 100 times brighter
- 25 times brighter
- 2 times brighter
- 50 times brighter


Question: The Pleiades is an open star cluster that plays a role in many ancient stories and is well-known for containing ... bright stars.

Choices:
- 5
- 7
- 9
- 12


Question: The nebular theory of the formation of the solar system successfully predicts all but one of the following. Which one does the theory not predict?

Choices:
- Planets orbit around the Sun in nearly circular orbits in a flattened disk.
- the equal number of terrestrial and jovian planets
- the craters on the Moon
- asteroids Kuiper-belt comets and the Oort cloud


Question: A sand bag has a mass of 5kg and weight 50N on Earth. What is the mass and weight of this sand bag on a planet with half the gravity compared to Earth?

Choices:
- Mass 5kg weight 100N
- Mass 5kg weight 50N
- Mass 5kg weight 25N
- Mass 10kg weight 100N


Question: Where is the crater from the impact that is believed to be responsible for the mass extinction of dinosaurs 65 million years ago?

Choices:
- Tunguska Siberia.
- Chicxulub Crater Yucatan Peninsula in Mexico.
- Quebec Canada.
- Meteor Crater in Arizona.


Question: In addition to the conditions required for any solar eclipse what must also be true in order for you to observe a total solar eclipse?

Choices:
- The Earth must lie completely within the Moon's penumbra.
- The Moon's penumbra must touch the area where you are located.
- The Earth must be near aphelion in its orbit of the Sun.
- The Moon's umbra must touch the area where you are located.


Question: What effect or effects would be most significant if the Moon's orbital plane were exactly the same as the ecliptic plane?

Choices:
- Solar eclipses would be much rarer.
- Solar eclipses would last much longer.
- Solar eclipses would be much more frequent.
- Solar eclipses would not last as long.


Question: What type of radiation causes a black hole to evaporate over time?

Choices:
- Schwarzschild radiation
- Planck radiation
- Kolmogorov radiation
- Hawking radiation


Question: Approximately how far away is the Andromeda Galaxy?

Choices:
- 1.7 million light years
- 2.1 million light years
- 2.5 million light years
- 3.2 million light years


Question: Which living organisms most resemble the common ancestor of all life according to genetic testing?

Choices:
- viruses
- bacteria such as E. coli
- organisms living deep in the oceans around seafloor volcanic vents and in hot springs
- plankton that use sunlight as an energy source through photosynthesis


Question: How did Eratosthenes estimate the size of the Earth in 240 B.C.?

Choices:
- By measuring the maximum altitude of the Sun in two cities at different latitudes at the same time on the same day.
- By measuring the size of Earth's shadow on the Moon during a lunar eclipse.
- By finding a place on Earth where the Sun passes directly overhead.
- By sending fleets of ships around the Earth.


Question: Our current best observations show that Pluto has

Choices:
- one medium sized satellite and two small satellites.
- no satellites.
- one large satellite and three small satellites.
- one large satellite.


Question: Pluto's extremely cold (~40 K) surface is composed of:

Choices:
- mainly water ice which always remains frozen
- nitrogen methane and carbon monoxide ices which sublimate into an atmosphere near perihelion
- nitrogen methane and carbon monoxide ices which always remain frozen
- roughly half ices and half rocky materials


Question: A Mars year is approximately how many Earth years long?

Choices:
- 1/2
- 1
- 2
- 4


Question: What is the correct numerical value and unit of the Boltzmann constant?

Choices:
- 1.38 × 10−21 m^3 · kg · s^−2 · K^−1
- 1.38 × 10−22 m^2 · kg · s^−3 · K^−1
- 1.38 × 10−23 m^2 · kg · s^−2 · K^−1
- 1.38 × 10−24 m^2 · kg · s^−2 · K^−2


Question: Which statement about an atom is not true:

Choices:
- The nucleus contains most of the atom’s mass but almost none of its volume.
- A neutral atom always has equal numbers of electrons and protons.
- A neutral atom always has equal numbers of neutrons and protons.
- The electrons can only orbit at particular energy levels.


Question: Earth has been gradually warming over the past few decades. Based on a great deal of evidence scientists conclude that this warming is caused by ________.

Choices:
- human activities that are increasing the concentration of greenhouse gases in Earth's atmosphere
- the fact that our politicians spout a lot of hot air
- the human release of chemicals called CFCs into the stratosphere
- the increase in forest fires during recent years


Question: How do scientists know that the majority of meteorites come from the asteroid belt?

Choices:
- The spectra of some meteorites are similar to the spectra of asteroids in the asteroid belt.
- The asteroid belt is the only possible source of meteorites therefore they must originate there.
- Collisions are common in the asteroid belt and we can track the fragments from their source asteroid to the Earth where they become meteorites.
- High levels of Iridum have been detected in both asteroids and meteorites therefore meteorites come from the asteroid belt.


Question: Which factor s most important in determining the history of volanism and tectonism on a planet?

Choices:
- size of the planet
- presence of an atmosphere
- distance from the sun
- rotation period