Question

A sample 76 obese adults was put on a special low carbohydrate diet for a
year. The average weight loss was 11 lb and the standard deviation was 19 lb
(note that, positive weight loss imply reduced weight over the time).
a. Calculate the 99% confidence interval for the true mean reduction.
b. Do you have sufficient evidence to believe that this diet program in
fact helps reduce weight?
c. If I tell you that any difference of less than 3 lb in mean weight loss is
not practically important, what is your conclusion about the practical
importance of the above results?

answer for a is (5.386, 16.614).

Please give me answer for b and c.

Answer 1

b)

here as our confidence interval contains all values above 0 ; which means we have 99% confidence from our interval that there is a significant weight loss.

hence we have sufficient evidence to believe that this diet program in fact helps reduce weight.

c)

as confidence interval has lower boundary above 3 lb ; that means we have 99% confidence to have weight loss more than 3 lb.

hence above given wieght loss by this diet is of practical importance.

(please revert for any clarification)