Question

A professor has noticed that, even though attendance is not a component of the final grade for the class, students that attend regularly generally get better grades. In fact, 57% of those who come to class on a regular basis receive A's. Only 16% who do not attend regularly get A's. The long run attendance rate is 81%. Based on this class profile find the following:__________

A) The percent who get A's given that they attend class regularly
B) The percent who get A's given that they do not attend class regularly
C) The overall percent of the students who get A's in the class
D) The percent who attend class regularly given that they get A's

Answer 1

A) 57%

B) 16%

C) 53%

D) 57%

Explanation:

Let R1 be students that attend class regularly

R2 be students that don't attend class regularly

A be students that receives A's in class

A) From the question A/R1 =57%

P(A/R1) = 0.57

B) From the question students that receive As that does not attend lectures regularly =16%

C) P(R2) = 1 -0.57 = 0.43

P(A) = P(A/R1) × P(R1) + P(A/R2)×P(R2)

P(A) = (0.57× 0.81) + (0.16×0

43)

P(A) = 0.46 + 0.0688= 0.53

The overall percentage that recieved A's = 53%

D) 57% recieved A's given that they attend class regularly.