TABLE 10-7 A Buyer for a Manufacturing Plant Suspects That His Primary

TABLE 10-7
A buyer for a manufacturing plant suspects that his primary supplier of raw materials is overcharging.In order to determine if his suspicion is correct,he contacts a second supplier and asks for the prices on various identical materials.He wants to compare these prices with those of his primary supplier.The data collected is presented in the table below,with some summary statistics presented (all of these might not be necessary to answer the questions which follow) .The buyer believes that the differences are normally distributed and will use this sample to perform an appropriate test at a level of significance of 0.01.
-A powerful women's group has claimed that men and women differ in attitudes about sexual discrimination.A group of 50 men (group 1) and 40 women (group 2) were asked if they thought sexual discrimination is a problem in the United States.Of those sampled,11 of the men and 19 of the women did believe that sexual discrimination is a problem.Assuming W designates women's responses and M designates men's,which of the following are the appropriate null and alternative hypotheses to test the group's claim?

A) H₀ : π_M - π_W ≤ 0 versus H₁: π_M - π_W > 0
B) H₀ : π_M - π_W ≥ 0 versus H₁: π_M - π_W < 0
C) H₀ : π_M - π_W = 0 versus H₁: π_M - π_W ≠ 0
D) H₀ : π_M- π_W ≠ 0 ≤ 0 versus H₁: π_M - π_W = 0