• In Example 4.12 in your textbook, it describes the Physician's Health Study that concluded those taking aspirin had a significantly lower chance of suffering a heart attack than those who took a placebo.
• 1. What other variables could have influenced this finding?
• 2. Would an in-depth study of the subject's current health status make a difference in deciding whether or not one could conclude that aspirin alone could be effective in preventing heart attacks?
• 3. Or can we believe the results of this study at face value?