Example 5.5 (page 120) analyzed data from a study that compared therapies for anorexia. For the 17 girls who received the family therapy, the changes in weight during the study were 11,11,6,9,14,-3,0,7,22,-5,-4, 13, 13,9,4,6,11.

(a) Verify that y 729 and s - 7.18 pounds.

(b) Verify that the standard error of the sample mean was 1.74.

(c) To use the distribution, explain why df = 16 and a 95% confidence interval uses the f-score of 2.120.

(d) Let denote the population mean change in weight for this therapy. Verify that the 95% confidence interval for is (3.6, 11.0). Interpret.