Exercise Set 13.2
10) Airline Fares Listed below are the cost (in dollars) of flights from New York (JFK) to San Francisco for US Air, Continental, Delta, United, American, Alaska, and Northwest. Use a 0.05 significance level to test the claim that there is no difference in cost between flights scheduled one day in advance and those schedule 30 days in advance. What appears to be a wise scheduling strategy?
Flight scheduled one day in advance 456 614 628 1088 943 567 536
Flight scheduled 30 days in advance 244 260 264 264 278 318 280
14) When testing gas pumps in Michigan for accuracy, fuel-quality enforcement specialists tested pumps and found that 1299 of them were not pumping accurately (within 3.3 oz. when 5 gal. is pumped), and 5686 pumps were accurate. Use a 0.01 significance level to test the claim of an industry representative that less than 20% of Michigan gas pumps are inaccurate.
Exercise Set 13.3
6) Listed below are actual high temperatures and the high temperatures forecast one day in advance (based on Data Set 11 in Appendix B). Use a 0.05 significance level to test the claim that the population of differences has a median of zero. What do the results suggest about the accuracy of the predictions?
Actual high temperature 80 77 81 85 73 73 80 72
High temperature forecast one day before 78 75 81 85 76 75 79 74
Exercise Set 13.4
8) Using the Wilcoxon rank-sum test.
Presidents and Popes: Refer to the longevity data below for U.S. presidents and popes. Use a 0.05 significance level to test the claim that the two samples are from populations with the same median.
Presidents 10 29 26 28 15 23 17 25 0 20 4 1 24 16 12 4 10 17 16 0 7 24 12 4 18 21 11 2 9 36 12 28 3 16 9 25 23 32
Popes 2 9 21 3 6 10 18 11 6 25 23 6 2 15 32 25 11 8 17 19 5 15 0 2
Monarchs 17 6 13 12 13 33 59 10 7 63 9 25 36 15
10) Cigarettes. Refer to attached data set for the amounts of tar in the sample of king size cigarettes, which are nonfiltered, nonmenthol, and non-light. Use a 0.01 significance level to test the claim that the median amount of tar in nonfiltered king size cigarettes is greater than the median amount of tar in 100 mm filtered cigarettes.
Exercise Set 13.5
12) Tar in Cigarettes. Refer to the attached data set 4 and use the amounts of tar (mg per cigarette) in the three categories of cigarettes. Use a 0.05 signifance level to test the claim that the three categories of cigarettes yield the same median amount of tar. Given that only the king size cigarettes are not filtered, do the filters appear to make a difference?
(Use the Kruskal-Wallis test with the data from Appendix B)
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