Question: According to a study published in the New England Journal o f Medicine, overweight people on lowcarbohydrate and Mediterranean diets lost more weight and got greater cardiovascular benefits than people on a conventional low-fat diet (The Boston Globe, July 17, 2008). A nutritionist wishes to verify these results and follows 30 dieters on the low-carbohydrate and Mediterranean diets and 30 dieters on the low-fat diet. These data (measured in pounds) can be found on the text website, labeled Different Diets.
a. Set up the hypotheses to test the claim that the mean weight loss for those on low-carbohydrate or Mediterranean diets is greater than the mean weight loss for those on a conventional low-fat diet.

b. Using the appropriate commands in Excel, find the value of the test statistic. Assume that the population variances are equal and that the test is conducted at the 5% significance level. What are the critical value(s) and the rejection rule?

c. At the 5% significance level, can the nutritionist conclude that overweight people on low-carbohydrate or Mediterranean diets lost more weight than people on a conventional low-fat diet?