chapter 1

Chapter 8: Tests of Hypotheses Based on a Single Sample76. H o : µ = 15 vs H a : > 15µ . Because the sample size is less than 40, and we can assume thedistribution is approximately normal, the appropriate statistic isx −1517.5 −152.5t = = = = 6.4s / n 2.2 / 32 .390column of Table A.8, and so is approximately . 05conclusion that the true average time exceeds 15 minutes.. Thus the p-value is “off the chart” in the 20 df0 < , so H o is rejected in favor of the77. H o : σ 2 = . 25 vs H a : σ2 > . 25upper-tail area .01 is 21.665. The test statistic value isnot ≥ 21. 665. The chi-squared critical value for 9 d.f. that captures9(.58).252= 12.11. Because 12.11 is, H o cannot be rejected. The uniformity specification is not contradicted.278. The 20 df row of Table A.7 shows that χ = 8.26 8. 58 (H o not rejected at level .01)and8.589.591=χ2.975,20. 99,20