Question

question 25
2.5 pts
suppose dr. karras wants to demonstrate that exercise causes people to have a lower level of stress. which of the following investigations should he do?
○ randomly assign people to different amounts of exercise. then measure stress to see if the high exercise group has lower stress.
○ identify people who exercise regularly and people who dont. measure stress to see if those who exercise regularly have lower stress.
○ both of the above
○ none of the above

Explanation:

To demonstrate a causal relationship (exercise causes lower stress), a true experimental design with random assignment is required. Randomly assigning participants to different exercise amounts controls for confounding variables, allowing causal inferences. The observational approach (identifying existing exercisers/non-exercisers) can only show correlation, not causation.

Answer:

A. Randomly assign people to different amounts of exercise. Then measure stress to see if the high exercise group has lower stress.