9.40 Anorexia in teenage girls Example 8 described a study about various therapies for teenage girls suffering from anorexia. For each of 17 girls who received the family therapy, the changes in weight were 11, 11, 6, 9, 14, -3, 0, 7, 22, -5, -4, 13, 13, 9, 4, 6, 11.

a. Plot these data with a dot plot or box plot and summarize.

b. Verify that the weight changes have x = 7.29, s = 7.18, and se = 1.74 pounds.

c. Give all steps of a significance test about whether the population mean was 0 against an alternative designed to see whether there is any effect.