Last year, Mr. Smith's biology class averaged 73 on their first test. This year, his new class averaged 87 on the same test. Based on these results, is it reasonable to conclude that this year's class is more intelligent?
O Yes, a grade of 87 is higher than a grade of 73.
O Yes, the study was done in an academic setting.
O No, the experiment was not double-blind.
No, there was no use of a placebo in the experiment.
O No, there may be other differences between the two years besides the grades.