Question

7.9 Wood et. al (1988) studied the efficacy of diet for losing weight. The study, which lasted one year, involved only men. The weight loss for dieting men follows a normal distribution with mean µ and standard deviation σ. A group of n = 16 dieting men lost an average of ¯x = 7.2 pounds with standard deviation s = 4.4 pounds. This problem will highlight the fact that a one-sided test has more statistical power than a two-sided test.

(c) Test H0 ∶ µ = 5.5 vs. Ha ∶ µ ≠ 5.5 at the α = 0.10 significance level. Find the test statistic and critical value, plot the rejection region, and state your decision and final conclusion.

(d) Approximate the p−value for the test in 7.9(c).

(e) Based upon your answer in 7.9(d), does the population mean weight loss µ significantly differ from 5.5 pounds? Why?

Answer 1