As part of the study described in Example 8.1.1(and in Exercise 8.5.3), involving the compound mCPP, weight change was measured for nine men. For each man two measurements were made: weight change when taking mCPP and weight change when taking the placebo. The data are given in the accompanying table.1

(a) What is the null hypothesis for a Wilcoxon signed-rank test here?
(b) Here is computer output for a Wilcoxon signed-rank test. Explain what the P-value means in the context of this study.
Wilcoxon signed rank test
data: mCpp and Placebo p-val ue = 0.4258
alternative hypothesis: true location shift is not equal to 0
(c) If α = 0.05, what is your conclusion regarding H0? State your conclusion in the context of the research.

Weight change Placebo mCPP Difference Subject 0.0 1.1 1.1 0.5 0.5 0.0 -0.5 1.3 1.4 0.0 0.8 -2.1 -0.3 -0.6 -2.2 0.9 0.7 -0.4 -0.3 -0.9 -0.5 0.7