A sociologist recently studied two sets of teenagers. The members of one set spent 10 or more hours per week watching violent television programs, and the members of the other set spent 2 hours or less per week watching violent television programs. A significantly greater proportion of the teenagers in the former group exhibited aggressive behavior during the period of the study. The sociologists reasoned that the prolonged exposure to television violence caused the aggressive behavior.
Which of the following, if true, of the teenagers in the study, provides the strongest challenge to the sociologist’s conclusion?

Question

Examsnet · Accepted Answer

Correct Answer is :  Many of the teenagers in the first group exhibited aggressive behavior before the study began.

GMAT Verbal Reasoning Practice Test 3