Question

A clinical trial is run to compare weight loss programs and participants are randomly assigned to one of the four comparison programs and are counseled on the details of the assigned program. Three popular weight loss programs were considered: the low calorie diet, the low fat diet, and the low carbohydrate diet . For comparison purposes, a fourth group is considered as a control group. Participants in the fourth group are told that they are participating in a study of healthy behaviors. After 8 weeks, each patient's weight is again measured and the difference in weights is computed by subtracting the 8-week weight from the baseline weight. Positive differences indicate weight losses and negative differences indicate weight gains. Observed weight losses are shown below.

Low calorie	Low fat	Low carb	Control
8	2	3	2
9	4	5	2
6	3	4	-1
7	5	2	0
3	1	3	3
3	3	3	-1
4	3	5	2
5	4	4	2
7	2	5	1
6	4	4	2
2	7	2	0
8	2	4	3

1. Using ANOVA determine if there are differences in weight loss among four groups:

• Set up null and alternative hypothesis
• Calculate the appropriate test statistic (Use ANOVA in excel)
• Provide interpretation of your results

2. Using ANOVA determine if there are differences in weight loss among ‘dieting’ groups (basically exclude the control group from the hypothesis testing)

• Set up null and alternative hypothesis
• Calculate the appropriate test statistic (Use ANOVA in excel)
• Provide interpretation of your results

3. What overall conclusions researchers can make based on the testing results from parts a and b?

Answer 1