Question: Manufacturing and Product Development The total weight (with the case) of a portable sewing machine is an important consideration. Suppose Singer claims to have the lightest machine by five pounds. Independent random samples of a Singer machine and a comparable Simplicity machine were obtained, and the weight (in pounds) of each was recorded. The summary statistics and known variances are given in the following table.
a. Is there any evidence to refute the claim made by Singer? Use a = 0.01.
b. Find the p value associated with this hypothesis test.
c. Is the normality assumption necessary in this problem? Why or why not?