Psychologists conducted a series of experiments to test the effect upon schoolchildren of violence in films. In the first experiment, grammar school children were shown a film that included scenes of a male teenager engaging in violent acts against others, such as punching, pushing, and kicking. During a free-play session following the film viewing, 42 percent of the children were observed to engage in one or more violent acts similar to those in the film. In a second experiment, a different group of children was shown a similar film featuring a female teenager. Only 14 percent of the children were observed behaving violently afterward. The psychologists concluded that children are more likely to imitate violent behavior on film when a male model is shown than when a female model is shown.
Which of the following, if true, would most seriously weaken the psychologists’ conclusion

Question

Examsnet · Accepted Answer

Correct Answer is :  The percentage of children known to have discipline problems prior to the experiment was greater in the first group than in the second group.

GMAT Verbal Reasoning Practice Test 2