Left-Tailed Hypothesis Tests and CIs. In Exercise 8.105 on page 374, we introduced one-sided one-mean z-intervals. The following relationship holds between hypothesis tests and confidence intervals for one-mean z-procedures: For a left-tailed hypothesis test at the significance level α, the null hypothesis H0: μ = μ0 will be rejected in favor of the alternative hypothesis Ha: μ<μ0 if and only if μ0 is greater than or equal to the (1 − α)-level upper confidence bound for μ. In each case, illustrate the preceding relationship by obtaining the appropriate upper confidence bound and comparing the result to the conclusion of the hypothesis test in the specified exercise.

a. Exercise 9.85

b. Exercise 9.86