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.

Question

Quizplus · Accepted Answer

The experiment involves a confounding because both the drug and the relaxation exercise were given to the experimental group, making it impossible to determine which of the two was responsible for any observed effects on anxiety. Without isolating the variables (i.e., giving one group the drug alone and another group the relaxation exercise alone), the effects of the drug and the exercise are confounded.

A Researcher Wanted to Compare the Relative Effectiveness of Two