In a double-blind study, researchers tested whether small doses of caffeine would improve highly trained male cyclists’ times in a hot environment (95°F, 25% humidity). The individuals were 9 highly trained male cyclists who rode a stationary bicycle in a hot climate chamber on three separate occasions. The first session was a familiarization session. On the second session, some athletes took a caffeine pill and the rest took a placebo pill of Metamucil. On the third session, each athlete took the other pill. For each of the second and third sessions, the cyclists were randomly assigned to the treatment and control groups. The study concluded that a small dose of caffeine improves a highly trained male cyclist’s time in a hot environment.
a. Describe the treatment and control groups.
b. Is the study an experiment or an observational study? Explain.
c. What does random assignment mean in this study? How could this be accomplished?
d. Describe the sample and the population.