Your roommate is conducting a survey to learn how many hours the typical student studies each day. She plans to pass out her questionnaire to the members of her sorority. You point out that her findings will be flawed because

A) she has not specified an independent variable.
B) she has not specified a dependent variable.
C) the sample will probably not be representative of the population of interest.
D) of all of these reasons.

The sample of her sorority members is not likely to be representative of the population of interest, which is all students. The sample needs to be randomly selected from a larger population for the findings to be generalizable. The lack of specification of independent and dependent variables does not necessarily invalidate the study, but the flaws in the sampling method make it difficult to draw reliable conclusions. Therefore, option C is the correct answer.