PLEASE Read the caffeine addiction study and complete a study analysis by answering the following questions. Refer to the lesson for details on the caffeine addiction study as needed. Be sure to answer each question completely.

1. What research question was investigated? 2. What design type was used: observational, experimental, or qualitative? Explain your answer. 3. How were subjects selected (or not selected) for the study? What (if any) impact did that process have? 4. What role did randomization play in this study? Specifically, did the researchers use randomization when selecting subjects for the study or when selecting the order in which the caffeine/placebo was given to the subjects? 5. In the study, neither the subjects nor the experimenters interviewing the subjects knew if the subject was receiving the caffeine pills or the caffeine-free pills. Why might this be an important design element in the study? 6. The subjects’ daily caffeine intakes were measured by evaluating their food diaries, where they recorded everything they consumed in one week’s time. What potential biases could there be in this type of record that would affect the caffeine intake measurement? 7. Can the results of this study be generalized? That is, would it be plausible to estimate that 16/27 (or 59%) of the general public is caffeine dependent? Why or why not? 8. Were the conclusions of the researchers reasonable considering the results of the study? Why or why not? 9. Is there anything in this study that leads you to believe that it lacks validity? Explain your answer.