ODD ANSWERS A89 23. (a) H0: Point of initial impact of crashes with occupant fatalities is independent from type of vehicle. Ha: Point of initial impact of crashes with occupant fatalities is dependent on type of vehicle. (claim) (b) d.f. = 2; x2 0 = 5.991; Rejection region: x 2 0 7 5.991 (c) 30.947 (d) Reject H0. (e) There is enough evidence at the 5% level of significance to conclude that point of initial impact of crashes with occupant fatalities is dependent on type of vehicle. 25. (a) H0: Procedure preference is independent of bank employee. Ha: Procedure preference is dependent on bank employee. (claim) (b) d.f. = 2; x2 0 = 5.991; Rejection region: x 2 7 5.991 (c) 88.361 (d) Reject H0. (e) There is enough evidence at the 5% level of significance to conclude that procedure preference is dependent on bank employee. 27. (a) H0: Type of car is independent of gender. (claim) Ha: Type of car is dependent on gender. (b) d.f. = 3; x2 0 = 6.251; Rejection region: x 2 7 6.251 (c) 0.808 (d) Fail to reject H0. (e) There is not enough evidence at the 10% level of significance to conclude that type of car is dependent on gender. 29. Fail to reject H0. There is not enough evidence at the 5% level of significance to reject the claim that the proportions of motor vehicle crash deaths involving males or females are the same for each age group. 31. Right-tailed 33. Educational attainment Status Not a high school graduate High school graduate Some college, no degree Associate’s, bachelor’s, or advanced degree Employed 0.037 0.148 0.088 0.335 Unemployed 0.004 0.009 0.005 0.011 Not in the labor force 0.050 0.119 0.059 0.136 35. (a) 1.1% (b) 5.9% 37. Educational attainment Status Not a high school graduate High school graduate Some college, no degree Associate’s, bachelor’s, or advanced degree Employed 0.061 0.243 0.145 0.551 Unemployed 0.127 0.317 0.175 0.381 Not in the labor force 0.137 0.328 0.163 0.373 39. 16.3% 41. 28.2 % Section 10.3 (page 555) 1. Specify the level of significance a. Determine the degrees of freedom for the numerator and denominator. Use Table 7 in Appendix B to find the critical value F. 3. (1) The samples must be random, (2) the samples must be independent, and (3) each population must have a normal distribution. 5. 2.54 7. 2.06 9. 9.16 11. 1.80 13. Fail to reject H0. There is not enough evidence at the 10% level of significance to support the claim. 15. Fail to reject H0. There is not enough evidence at the 1% level of significance to reject the claim. 17. Reject H0. There is enough evidence at the 1% level of significance to reject the claim. 19. (a) H0: s 2 1 … s 2 2; Ha: s 2 1 7 s 2 2 (claim) (b) F0 = 2.45; Rejection region: F 7 2.45 (c) 2.17 (d) Fail to reject H0. (e) There is not enough evidence at the 2.5% level of significance to support Company A’s claim that the variance of the life of its appliances is less than the variance of the life of Company B’s appliances. 21. (a) H0: s 2 1 = s 2 2; Ha: s 2 1 ≠ s 2 2 (claim) (b) F0 = 3.18; Rejection region: F 7 3.18 (c) 7.31 (d) Reject H0. (e) There is enough evidence at the 10% level of significance to conclude that the variances of the driving distances differ between the two golfers. 23. (a) H0: s 2 1 = s 2 2 (claim); Ha: s 2 1 ≠ s 2 2 (b) F0 = 2.635; Rejection region: F 7 2.635 (c) 1.282 (d) Fail to reject H0. (e) There is not enough evidence at the 10% level of significance to reject the administrator’s claim that the standard deviations of science assessment test scores for eighth-grade students are the same in Districts 1 and 2. 25. (a) H0: s 2 1 … s 2 2; Ha: s 2 1 7 s 2 2 (claim) (b) F0 = 1.59; Rejection region: F 7 1.59 (c) 2.240 (d) Reject H0. (e) There is enough evidence at the 5% level of significance to conclude that the standard deviation of the annual salaries for actuaries is less in California than in New York. 27. Right-tailed: 14.73; Left-tailed: 0.15 29. (0.340, 3.422) Section 10.4 (page 565) 1. H0: m1 = m2 = m3 = g= mk Ha: At least one of the means is different from the others. 3. The MSB measures the differences related to the treatment given to each sample. The MSW measures the differences related to entries within the same sample. 5. (a) H0: m1 = m2 = m3 Ha: At least one mean is different from the others. (claim) (b) F0 = 3.89; Rejection region: F 7 3.89 (c) 1.325 (d) Fail to reject H0. (e) There is not enough evidence at the 5% level of significance to conclude that at least one mean cost per ounce is different from the others.
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