Question

Below, the two-way table is given for aclass of students.FreshmenSophomoreJuniorsSeniorsTotalMale4622Female3463TotalIf a student is selected at random, find theprobability the student is a male given that it'sa senior. Round to the nearest whole percent.[?]%

Answer 1

We have to calculate the probability that a student selected at random is a male given that it is a senior.

This probability can be written as the quotient between the probability that a student is male and senior and the probability that the student is a senior:

`P(M|S)=(P(M\cap S))/(P(S))`

We have 2 male and seniors, and there are 2+3=5 seniors (including male and female).

Then, being N the sample size, we can write:

`P(M|S)=(P(M\cap S))/(P(S))=((2)/(N))/((5)/(N))=(2)/(5)=0.4=40\%`

Answer: 40%