4. Let's assume you endeavor to compare the effectiveness of sleep aids taken by pi- lots who are assigned international flights relative to how restful they feel, which is a self-reported response that can vary from 1 = "not very restful" to 5 = "extremely rest- ful." Let's further assume that your primary focus is comparing over-the-counter aids such as melatonin to prescription drugs such as Lunesta as well as to a control group of pilots who do not use any type of sleep aid. Which statistical strategy is appropriate for this study?

a. Single-sample t test because you are comparing a sample mean to a control group.

b. Independent-samples t test because you are comparing two groups.

c. Single-factor ANOVA because you are comparing three groups.

d. Regression because you want to be able to predict pilots' level of "restfulness."