To Evaluate the Objectivity of a Certain Professor's Grading, 20

Multiple Choice

To evaluate the objectivity of a certain professor's grading, 20 classes that she previously taught are randomly selected for auditing.The proportion of male students who pass in each class is compared to the proportion of female students who pass in the same selected class.The sample in this study is:

A) the comparison of male and female passing rates for the classes.
B) the proportion of all males who passed and the proportion of all females who passed.
C) the 20 selected classes.
D) a single selected class.