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[bryan88]

According to a school survey conducted last month, the number of students who regularly attend religious services on campus has increased fifty percent from the figure ten years ago. It must be this increased religiosity at our college that has led to a recent, massive reduction of incidences of cheating on exams.

Which of the following, if true, most significantly weakens the inference above?

A)Most of the students who now attend campus services do so only for social reasons.
B)Campus chaplains have time and again spoken about the importance of academic honesty.
C)Fifteen years ago, the college switched from an honor system to faculty-proctored exams.
D)Only freshmen and sophomores responded to the survey.
E)Cheating was never a major problem at this school.

[Bill@VeritasPrep]

Premise 1: religious attendance is up 50%
Conclusion: this increased religiosity has decreased cheating on exams

We're looking for something that will cast doubt on the likelihood of that conclusion.

A--Bingo. If students are attending for social reasons, then it's plausible that the student body is not more religious now than it was 10 years ago. If true, then the drop in cheating must be due to another factor.
B--This would strengthen the conclusion
C--Seems tempting, but the change occurred before the increase in religiosity. Since the drop in cheating is recent, this doesn't work
D--There was no mention of class breakdown
E--Irrelevant; even if it's a minor problem, religiosity could reduce it