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Unformatted text preview: 140 CHAPTER 9. HYPOTHESIS TESTING: SINGLE MEAN AND SINGLE PROPORTION 9.2 Homework (modified R. Bloom) 2 Some exercises from the original version of this textbook have been removed in this revision of this section: #11,12,14,18-24,26,27. They are available at http://cnx.org/content/m17001/ Exercise 9.1 (Solution on p. 149.) Some of the statements below refer to the null hypothesis, some to the alternate hypothesis. State the null hypothesis, H o , and the alternative hypothesis, H a , in terms of the appropriate pa- rameter ( μ or p ). a. Americans work an average of 34 years before retiring. b. At most 60% of Americans vote in presidential elections. c. The average starting salary for San Jose State University graduates is at least $100,000 per year. d. 29% of high school seniors get drunk each month. e. Fewer than 5% of adults ride the bus to work in Los Angeles. f. The average number of cars a person owns in her lifetime is not more than 10. g. About half of Americans prefer to live away from cities, given the choice. h. Europeans have an average paid vacation each year of six weeks. i. The chance of developing breast cancer is under 11% for women. j. Private universities cost, on average, more than $20,000 per year for tuition. Exercise 9.2 (Solution on p. 149.) For (a) - (j) above, state the Type I and Type II errors in complete sentences. Exercise 9.3 For (a) - (j) above, in complete sentences: a. State a consequence of committing a Type I error. b. State a consequence of committing a Type II error. NOTE: For each of the word problems, use a solution sheet to do the hypothesis test. NOTE: If you are using a student-t distribution for a homework problem below, you may assume that the underlying population is normally distributed. (However, in general, a statistician would first need to verify that this assumption is reasonable before applying a t-test.) Exercise 9.4 A particular brand of tires claims that its deluxe tire averages at least 50,000 miles before it needs to be replaced. From past studies of this tire, the standard deviation is known to be 8000. A survey of owners of that tire design is conducted. From the 28 tires surveyed, the average lifespan was 46,500 miles with a standard deviation of 9800 miles. Do the data support the claim at the 5%46,500 miles with a standard deviation of 9800 miles....
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- Fall '08
- Statistics, Null hypothesis, Statistical hypothesis testing