Well, we don't know the background of the study or the reasoning for using such a small sample size. Maybe it was part of a project or some other type of classwork? I mean, in order to understand on a broader level the implications of a study have you must look at the source of the sample:

a) do these kids have other circumstances which make them get these GPAs aside from just staying up all night.

b) What are the relative IQs or the study habits of those who don't do the all-nighters vs. those who do.

c) Is there a method to change this incidence of lower GPAs such as implementation of a study skills/time management course.

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B.S. Boston University Medical School(Biomed)
A.L.B. Harvard University(Biology)