In a finance class, the final grade is based on three tests. Historically, the instructor tells the class that the joint probability of scoring "A"'s on the first two tests is 0.5. A student assigns a probability of 0.9 that she will get an "A" on the first test. What is the probability that the student will score an "A" on the second test given that she scored an "A" on the first test?
A) 0.50
B) 0.95
C) 0.55
D) 0.90

Question

Quizplus · Accepted Answer

The probability of scoring "A" on both tests is 0.5, and the probability of scoring "A" on the first test is 0.9. Using conditional probability: P(A2|A1) = P(A1 and A2) / P(A1) = 0.5 / 0.9 = 0.55.

In a Finance Class, the Final Grade Is Based on Three