Grades of Students in Psychology A B C Total Freshman 10 0 7 17 Sophomore 2 8 Junior 10 4 3 17 Total 20 10 12 42 What is the probability that a student has a B in Psychology given that they are a Sophomore? P(AUB)= P(A)+P(B)-(PNB) P(AUB)= (10/42)+(8/42)-(6/42) P(AUB)= .2857 What is the probability that a student is a Freshman given that they have a B in Psychology