In: Math
Giving a test to a group of students, the grades and gender are
summarized below
A | B | C | Total | |
Male | 6 | 11 | 2 | 19 |
Female | 10 | 13 | 15 | 38 |
Total | 16 | 24 | 17 | 57 |
If one student is chosen at random,
Find the probability that the student was NOT a female that got a
"B"
We have to find the probability that the selected student was Not a female given that got a B
Using the formula P(A|B) = P(not a female AND got a B)/P(got a B)
we can write P(Not a female given that got a B) = P(not a female AND got a B)/P(got a B).......equation 1
First, we will find the probability that the selected student is not a female AND got a B
total students = 57 and not a female means male only = 11
we have favourable outcome= 11 and total outcome = 57
So, P(not a female AND got a B) = 11/57
Now, probability of getting a B = favourable/total
favourable outcome for getting a B = 24 and total outcome = 57
So, P( got a B) = 24/57
setting the value of P(not a female AND got a B) and P( got a B) in the formula in equation 1
we get
P(Not a female given that got a B) = P(not a female AND got a B)/P(got a B) = (11/57)/(24/57) = 11/24 or 0.4583
Therefore, required probability is 11/24 or 0.4583