P.3.7

Suppose that a birth is equally likely to be a boy or girl. And the outcome of one birth does not change this probability for future births.

• Describe how you could use a coin to approximate the probability that a couple with four children would have 2 boys and 2 girls.
• It turns out that the probability is 0.375 that a couple with four children would have 2 boys and 2 girls. Interpret what this probability means.
• Based on the probability given in part b), what is the probability that a couple with four children does not have 2 boys and 2 girls?
• Explain why it makes sense (at least in hindsight) that a couple with four children is more likely not to have 2 of each sex than to have 2 of each sex.