Question

In a class of students, the following data table summarizes how many students have abrother or a sister. What is the probability that a student has a brother given that theydo not have a sister?

Answer 1

We have to calculate the probability that a student has a brother given that they do not have a sister.

We can find this probability as the quotient between P1, the probability of a student having a brother and no sister, and P2, the probability of a student having no sister.

The total amount of students is 29.

So we can write:

`P(B|noS)=(P(B\cap noS))/(P(noS))=((6)/(29))/((6)/(29)+(18)/(29))=(6)/(6+18)=(6)/(24)=0.25`

Answer:

The probability that a student has a brother given that they do not have a sister is P=0.25.