WS5_Unit 1 MC Review

Unit 1 Multiple Choice Review Name: AP Statistics, Unit 1 WS 5 Period: Date: Note: it must be clear by the evidence on your paper that you actually worked these problems out, and didn’t just circle answers randomly. 1. The following is a histogram showing the actual frequency of the closing prices on the New York exchange of a particular stock. Based on the frequency histogram, the class that contains the 80th percentile is: (a) 20-30 (b) 10-20 (c) 40-50 (d) 50-60 (e) 30-40 2. Which of the following is likely to have a mean that is smaller than the median? (a) The scores of students on a very easy exam in which most get nearly perfect scores but a few do very poorly. (b) The salaries of all National Football League players. (c) The prices of homes in a large city. (d) The scores of students on a very difficult exam in which most get poor scores but a few do very well. (e) Winnings at a casino. 3. There are three children in a room, ages three, four, and five. If a four-year-old child enters the room the (a) mean age stays same but the standard deviation will increase. (b) mean age and standard deviation will stay the same. (c) mean age stays same but standard deviation will decrease. (d) mean age and standard deviation will increase. (e) mean age and standard deviation will decrease. 4. Based on these boxplots, which of the following is the most plausible conclusion about the data collected? (a) The interquartile range for each class is not the same. (b) There are more scores that are greater than 2 for Class A than there are for Class B. (c) There are more scores that are greater than 3 for Class A than there are for Class B. (d) All students in the lower 25% of both classes had a score of 1. (e) More students in Class B scored a 1 than in Class A. 5. If the mean of a data set is 12.3 and standard deviation is 0, then (a) there must have been a mistake in the calculation, as it is not possible to have a standard deviation of 0. (b) a histogram of the data set has a single peak at zero. (c) a histogram of the data set will be strongly skewed. (d) there is a large amount of variability in the data set. (e) all of the observations are equal to 12.3. 6. Six hundred travelers have purchased airline tickets through the same travel agency. The following table gives the two-way classification of their destination choices. The following is the conditional distribution of female travels, except one. Which is incorrect? Male Female Totals Europe 189 195 384 Asia 49 62 111 South America 55 50 105 Totals 293 307 600 (a) Europe: 63.5% (b) Asia: 20.2% (c) SA: 16.3% (d) All correct. 7. A researcher wishes to calculate the average height of patients. From patient records, the mean was computed as 156 cm and standard deviation as 5 cm. Further investigation reveals that the scale was misaligned, and that all readings are 2 cm too large, e.g., a patient whose height is really 180 cm was measured as 182 cm. Furthermore, the researcher would like to work with statistics based on meters. The correct mean and standard deviation are: (a) 1.56m, 0.05m (b) 1.54m, 0.05m (c) 1.56m, 0.03m (d) 1.58m, 0.05m (e) 1.58m, 0.07m 8. The weight (in ounces) of packages of cheddar cheese are given on the table below. How many packages weighted less than 24 ounces and what percent of packages weighed more than 20 ounces? (a) 8; 37.5% (b) 8; 62.5% (c) 14; 37.5% (d) 14; 62.8% 9. The median age of five people in a meeting is 30 years. One of the people, whose age is 50 years, leaves the room. The median age of the remaining four people in the room is (a) 25 years. (b) 30 years. (c) 40 years. (d) less than 30 years. (e) Cannot be determined from the information given. 10. Which is true of the data shown in the boxplot below? I. The median and IQR summarize the data better than the mean and standard deviation because there appear to be outliers. II. The mean and median are approximately equal. III. The median and IQR summarize the data better than the mean and standard deviation because the data is skewed. (a) I only (b) III only (c) I and II (d) I and III (e) I, II, and III 11. The mean salary of all female workers in company X is $35,000. The mean salary of all male workers in company X is $41,000. There were more men than females in the company. What must be true about the mean salary of all workers?

(a) It must be $38,000. (b) It must be larger than the median salary. (c) It could be any number between $35,000 and $41,000. (d) It must be larger than $38,000. (e) It cannot be larger than $40,000. 12. The season’s scores for the football teams going to the state championship are given in the stem-and-leaf plot below. Which team had the wider range? key: 3|7 = 37 points (a) Team A with 42 (b) Team A with 23 (c) Team A with 30 (d) Team B with 33 (e) Team B with 26 13. The five-number summary for scores on a statistics exam is 11, 35, 61, 70, and 79. In all, 380 students took the test. About how many students had scores between 35 and 61? (a) 95 (b) 26 (c) 54 (d) 190 (e) 76 14. The heights of American men aged 18 to 24 can be modeled with the following distribution: N(68in., 2.5in). About 16% of all these young men are shorter than (a) 65.5 inches (b) 68 inches (c) 70.5 inches (d) 73 inches (e) 63 inches 15. Use the information in the previous problem. Only about 5% of young men have heights outside the range (a) 65.5 inches to 70.5 inches (b) 63 inches to 73 inches (c) 60.5 inches to 75.5 inches (d) 58 inches to 78 inches (e) below 73 inches 16. Increasing the frequencies in the tails (i.e. putting more data in the ends) of a distribution will: (a) not affect the standard deviation as long as the increases are balanced on each side of the mean (b) not affect the standard deviation (c) increase the standard deviation (d) reduce the standard deviation (e) none of the above 17. The area under the standard normal curve for –0.3 < Z < 1.6 is (a) 0.3273 (b) 0.4713 (c) 0.5631 (d) 0.9542 (e) 0.6458 18. Suppose that sixteen-ounce bags of chocolate chips cookies are produced with an actual mean weight of 16.3 ounces and a standard deviation of 0.2 ounce. The weights are approximately normally distributed. Approximately what percentage of the bags will likely be underweight (i.e., less than 16 ounces)? (a) 0.06 (b) 5 (c) 7 (d) 12 (e) 16 19. This is a continuation of Question 18. The largest 1% of the bags are too full to close properly. What is the minimum weight, in ounces, of these overstuffed bags? (a) 0 (b) 15.8 (c) 16.0 (d) 16.8 (e) 18.3 20. If the heights of 99.7% of American men is are between 5 ' 0 " and 7 ' 0 " , what is your estimate of the standard deviation of the heights, given that their heights are normally distributed? (a) 1” (b) 3” (c) 6” (d) 4” (e) 12” 21. The mean of the weights of a group of 100 men and women is 160lb. If the number of men in the group is 60 and the mean weight of the men is 180lb, what is the mean weight of the women? (a) 120lb (b) 125lb (c) 130lb (d) 132lb (e) 135lb 22. Suppose that a Normal model described student scores in a history class. Phil has a standardized score ( z -score) of − 2.5 . This means that Phil (a) is 2.5 points below average for the class. (b) is 2.5 standard deviations below average for the class. (c) has a standard deviation of 2.5 points (d) has a score 2.5 times smaller than the average for the class. (e) None of the above. 23. Computer output gives these summaries Are there outliers? Min Q1 Median Q3 Max 7.9 10.8 13.4 16.7 25.8 (a) no low outliers since min is above 1.95 (b) at least one high outlier since max is greater than 25.55 (c) exactly one high outlier since max is great than 25.55 (d) both (a) and (b) above (e) both (a) and (c) above 24. A machine that fills 12 oz cans with soda fills according to a Normal model with mean 12.1 ounces. Management wants to ensure that only 1% of cans are under-filled. What standard deviation does the filling machine need to have to achieve this? (a) 0.0429 (b) 0.121 (c) -2.33 (d) 0.0215 25. The mean number of points per game scored by basketball players during the championship is 9.4, and the standard deviation is 1.5. Assuming that the number of points are normally distributed, what number of points per game will place a player in the top 15% players taking part in the basketball championship? (a) 7.85 points per game (b) 9.10 points per game (c) 10.95 points per game (d) 12.35 points per game (e) 13.96 points per game 26. Two sections of a class took the same quiz. Section A had 15 students who had a mean score of 80, and Section B had 20 students who had a mean score of 90. Overall, what was the approximate mean score for all of the students on the quiz? A) 84.3 B) 85.0 C) 85.7 D) none of these E) It cannot be determined