The qualifications of an incoming academic class depend on the relationship between qualifications and admission (decision by the school whether to admit), as well as the relationship between qualifications and matriculation (decision by an admitted student whether to attend). This Demonstration shows the effects of different admission policies and different matriculation decisions on the "class profile": the distribution of qualifications among the students that end up attending.
The grayish curve is the relationship between the criteria (like SAT score or GPA) and the probability of being offered admission. The orange curve is the relationship between the criteria and the probability that a student offered admission will accept ("matriculate"). The brown curve is thus the probability that a student with a given criteria will end up attending the school. Change the curves by dragging the locators.