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Unformatted text preview: STATISTICS SECTION I Time 1 hour and 30 minutes Number of questions 40 Percent of total grade 50 Directions : Solve each of the following problems, using the available space for scratch work. Decide which is the best of the choices given and fill in the corresponding oval on the answer sheet. No credit will be given for anything written in the test book. Do not spend too much time on any one problem. 1. The statistics below provide a summary of the distribution of heights, in inches, for a simple random sample of 200 young children. Mean: 46 inches Median: 45 inches Standard Deviation: 3 inches First Quartile: 43 inches Second Quartile: 48 inches About 100 children in the sample have heights that are (a) less than 43 inches (b) less than 48 inches (c) between 43 and 48 inches (d) between 40 and 52 inches (e) more than 46 inches 2. In which of the following situations would it be most difficult to use a census? (a) To determine what proportion of licensed bicycles on a university campus have lights. (b) To determine what proportion of students in a high school support wearing uniforms. (c) To determine what proportion of registered students enrolled in a college are employed more than 20 hours each week. (d) To determine what proportion of single-family dwellings in a small town have two-car garages. (e) To determine what proportion of fish in Lake Michigan are bass. 3. The distribution of the diameters of a particular variety of oranges is approximately normal with a standard deviation of 0.3 inch. How does the diameter of an orange at the 67 th percentile compare with the mean diameter? (a) 0.201 inch below the mean (b) 0.132 inch below the mean (c) 0.132 inch above the mean (d) 0.201 inch above the mean (e) 0.440 inch above the mean //home/vdimitrov/14150/ed32c4ccf8ae7d8693c9cfbbecdc331ea14370fa.doc 4. Independent random samples of 100 luxury cars and 250 non-luxury cars in a certain city are examined to see if they have bumper stickers. Of the 250 non-luxury cars, 125 have bumper stickers and of the 100 luxury cars, 30 have bumper stickers. Which of the following is a 90 percent confidence interval for the difference in the proportion of non-luxury cars with bumper stickers and the proportion of luxury cars with bumper stickers from the populations of cars represented by these samples? (a) ( 29 ( 29 ( 29 ( 29 ( 29 100 7 . 3 . 250 5 . 5 . 645 . 1 3 . 5 . + - (b) ( 29 ( 29 ( 29 ( 29 ( 29 100 7 . 3 . 250 5 . 5 . 96 . 1 3 . 5 . + - (c) ( 29 + - 100 1 250 1 350 195 350 155 645 . 1 3 . 5 . (d) ( 29 + - 100 1 250 1 350 195 350 155 96 . 1 3 . 5 ....
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