Given equal probabilities of the birth of a boy or girl, what is the probability that a group of three siblings includes exactly two boys? Exactly three boys? Two or more boys?

Question

Quizplus · Accepted Answer

The probability of exactly two boys is 3/8 because there are three combinations (BBG, BGB, GBB) out of eight possible combinations (BBB, BBG, BGB, GBB, GGG, GGB, GBG, BGG) that satisfy this condition. The probability of exactly three boys is 1/8 because there is only one combination (BBB) out of eight that satisfies this condition. The probability of having two or more boys is the sum of the probabilities of having exactly two boys and exactly three boys, which is 3/8 + 1/8 = 1/2.

Given Equal Probabilities of the Birth of a Boy or Girl