For each of the following situations, draw a picture illustrating the process used in the study. The picture should be similar to whichever of a figure 5.1, 5.2, or 5.3 is most appropriate for the situation.
a. The study described in Example 5.2 on page 97, “Blindly lowering cholesterol.”
b. The study described in Case Study 5.1 on page 98, “Quitting smoking with nicotine patches.”
c. The study described in Exercise 4 on page 113, in which a utility company randomly as-signed volunteers to two different rate plans and compared usage.