In a study, people who drink coffee have a lower rate of a disease, but coffee drinkers also exercise more. What is exercise called in this study?
Answer and explanation
Correct answer: A. A confounding variable
- Step 1: Exercise is related to both coffee and the disease. Step 2. It can explain the observed pattern. Answer: a confounding variable. Why not the others: The explanatory variable is coffee consumption; the response variable is heart disease incidence; and a placebo is an inert control treatment in experimental trials.
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