Mrs Jones’s children, cont. Instead of telling you that at least one of the children is a girl, Mrs Jones tells you that her oldest child is a girl. Now, what is the probability that the other child is also a girl?

Mr Peters’s children Your other neighbor, Mr Peters, has three children. Having just moved to the neighborhood, you do not know whether the children are boys or girls. Let us assume that every time Mr Peters had a child, he was equally likely to have a boy and a girl (and that there are no other possibilities).

(a) What is the relevant outcome space?

(b) Imagine that you learn that at least one of the children is a girl. What is the new outcome space?

(c) Given that you know that at least one of the children is a girl, what is the probability that Mr Peters has three girls?

(d) Imagine that you learn that at least two of the children are girls. What is the new outcome space?

(e) Given that you know that at least two of the children are girls, what is the probability that Mr Peters has three girls?