Question

A researcher wanted to compare the relative effectiveness of two techniques for reducing anxiety: a drug and a relaxation exercise. The researcher gave the experimental group both the drug and the relaxation exercise. The control group was given neither the drug nor the exercise. The difference between the drug and the relaxation exercise cannot be compared in this experiment because the experiment involves a
A. redundant relationship.
B. correlation.
C. causal inference.
D. confounding.

Answer

This answer is hidden. It contains 1 characters.