A study compared various therapies for the teenage girls suffering from anorexia, an eating disorder. For each and every girl, weight was measured before and after fixed period of treatment. The variable measured was change in weight, X = weight at the end of study minus weight at beginning of the study. The therapies were designed to aid weight gain, corresponding to positive values X. For the sample of 17 girls receiving the family therapy, the changes in weight during the study were:
11, 11, 6, 9, 14, -3, 0, 7, 22, -5, 04, 12, 13, 9, 4, 5, 11
a. ignore this one.
b. using a calculator, show that the weight changes have x bar=7.29 and s=7.18 pounds.
c. using a calculator, show that the standard error of sample mean was se=1.74
d. to use the t distribution, explain why the 95% confidence interval uses the t-score equal to 2.120
e. let? denote the population mean change in weight for this therapy. using results from b,c,d show that the 95% confidence interval for? is (3.6, 11.0). explain why this suggests that the true mean change in weight is positive, but possibly quite small.