17. Four individuals with high levels of cholesterol went on a special crash diet, avoiding high-cholesterol foods and taking special supplements. Their total cholesterol levels before and after the diet were as follows:

Participant Before After J. K. 287 255 L. M. M 305 269 A. K. 243 245 R. O. S. 309 247 Using the .05 level of significance, was there a significant change in cholesterol level?

(a) Use the steps of hypothesis testing.

(b) Sketch the distributions involved.

(c) Explain your answer to someone who has never taken a course in statistics.