PRACTICE FINAL Time: 120 minutes You must show your work. If you use a calculator, you must state what keys you pressed, *and* what the calculator showed as the result of the calculation. If you merely state the right answer but show no work to support it, or your work does not support your answer, you will not receive credit. 1. LaTonya is in the 25% tax bracket. Gail is in the 15% tax bracket. They each itemize their deductions and they each donate $2000 to charity. Compare their true costs for charitable donations. What is the difference between LaTonya's true costs and Gail's true costs? A. No difference B. $200 C. $300 D. $500 2. In its first year in business, TechnoTech Inc. had outlays of $400,000 and receipts of $200,000. In its second year, the company had outlays of $200,000 and receipts of $300,000. Which of the following correctly describes TechnoTech's first two years in business? A. Surplus in both years B. Surplus in the first year, deficit in the second year C. Deficit in the first year, surplus in the second year D. Deficit in both years 3. A study is done to determine whether there is a correlation between people's weight and their income. 1000 people chosen randomly from the phone book are asked to report their weight and their income. How would you describe this study? A. Single-blind experiment B. Double-blind experiment C. Case-control observational study D. Non-case-control observational study 4. A pollster stops random people at a busy intersection and asks them "Do you support the administration's policies?". What is likely to be the main problem with this survey? A. Selection bias B. Participation bias C. Confounding variables D. Setting and wording 5. A pollster conducted a single-question survey in which the question had five different possible responses. She summarized the results of her poll with a histogram, but two of the percentage-labels got erased: | 36% | ___ 28% | | | ___ | | | | | | | | | | ___ 12% | | | | | | | ___ | | | | | | | | | ___ |___|___|___|___|___|___|___|___|___|___|___ What are the two missing labels? A. 18% and 6% B. 12% and 12% C. 8% and 4% D. Any of the above could be correct; there is not enough information 6. Examine the stack plot shown on page 345. [If this were a real exam, I'd include a photocopy in the exam booklet.] Compare the death rate (per 100,000 people) for cardiovascular disease in 1900 with the combined death rates for pneumonia, tuberculosis, and cancer in that same year. Which of the following best describes the comparison? A. Significantly more people in 1900 died of cardiovascular disease than died of pneumonia, tuberculosis, and cancer combined. B. Significantly fewer people in 1900 died of cardiovascular disease than died of pneumonia, tuberculosis, and cancer combined. C. About the same number of people in 1900 died of cardiovascular disease as died of pneumonia, tuberculosis, and cancer combined. D. One can't tell (there is not enough information). 7. Examine the following scatter diagram, in which the horizontal axis is IQ and the vertical axis is shoe-size: __________________________________________ 11| | | * * | 10| * * | | | 9| * * | | | 8| * * | | | 7| * * | | | |__________________________________________| 80 90 100 110 120 What sort of correlation does this diagram display? A. Positive correlation B. Negative correlation C. No correlation D. Question does not make sense because there is no cause-and-effect relationship between shoe-size and intelligence 8. Consider a data set with a histogram of the following shape: 7 | --- 6 | | | 5 | | | --- 4 | | | | | --- 3 | | | | | | | --- --- 2 | --- | | | | | | | | | | 1 | | | | | | | | | | | | | -------------------------------------------------- 1 2 3 4 5 6 What is the relationship between the median and the mode of the data set? A. The median is greater than the mode B. The median is smaller than the mode C. The median equals the mode D. It is impossible to tell from the information provided 9. Compare the standard deviations of two data sets called "X" and "Y": Data set X: 2 ft., 2 ft., 3 ft., 4 ft., 4 ft. Data set Y: 28 in., 28 in., 30 in., 32 in., 32 in. A. Data set X has larger standard deviation than data set Y B. Data set Y has larger standard deviation than data set X C. The two data sets have the same standard deviation D. It is impossible to compare 10. Suppose that the scores of some students on some test are governed by a normal distribution. The mean score of the students was 85 points, and about 70% of the students scored between 80 points and 90 points. What is the best estimate of the standard deviation? A. 2.5 points B. 5 points C. 70 points D. 85 points 11. A hospital administrator claims that the mean stay at her hospital is greater than the national average of 2.1 days. She decides to do a study of 81 women at her hospital, and she finds that for the women in her sample, the mean hospital stay after childbirth is 2.3 days. A statistical table tells her that if the average at her hospital were the same as the national average, the probability of observing a sample with a mean of 2.3 days or more would be 0.17. What should she do? A. She should reject the null hypothesis with a statistical significance at the 0.01 level. B. She should reject the null hypothesis with a statistical significance at the 0.05 level (but not at the 0.01 level). C. She should fail to reject the null hypothesis. D. She should accept the null hypothesis. 12. A casino offers two games: "Chump Change" and "Dingbat Dollars". "Chump Change" costs $1 to play. 20% of the time, you double your money (profit = $1); 50% of the time, you just get a dollar back (profit = $0); and 30% of the time, you get nothing back (profit = -$1). "Dingbat Dollars" also costs $1 to play. 30% of the time, you get $3 back (profit = $2); the rest of the time, you get nothing (profit = -$1). Which game is more favorable to you in the long run? That is, which game will result in your winning money at a faster rate (or at least losing money at a slower rate) if you play it long enough and the law of large numbers applies? A. Chump Change is the better game to play B. Dingbat Dollars is the better game to play C. Both games are equally good D. There is not enough information to decide