A "water dieť" requires you to drink one cup of water every hour from the time you get up until you go to bed, but otherwise allows you to eat whatever you like. Four adult volunteers agree to follow the diet. They are
weighed prior to beginning the diet and after six weeks on the diet. The weights (in pounds) are:
Subject
Weight before diet
Weight after diet
A
180
B
125
130
с
240
D
150
152
170
215
4. Which of the following conditions must be met in order to use a t procedure on these paired data?
(a) The distribution of before-diet weights must be approximately Normal.
(b) The distribution of differences (before - after) must be approximately Normal.
(c) The distribution of both before-diet weights and after-diet weights must be approximately Normal.
(d) The distribution of before-diet weights and the distribution of differences (before - after) must be
approximately Normal
(e) All three distributions of weight (before-diet, after-diet, and the differences) must be approximately
Normal.