>If the man is randomly chosen from the set of all families the answer is 1/... | Hacker News

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anorwell on Nov 29, 2011 | parent | context | favorite | on: Think you understand Monty Hall? Try the Tuesday b...

>If the man is randomly chosen from the set of all families the answer is 1/2.

By assumption, the man has a son born on Tuesday, so this is hardly relevant.

If A is a subset of B, then choosing x uniformly at random from A given that x is in B is the same as choosing uniformly at random from B.

monorailkitty on Nov 30, 2011 [–]

I agree but set B is not a uniformly chosen subset of A in this case. That is the core of the trick. The rule for choosing B is intuitively uniform but actually slightly favours families with a girl and a boy over those with two boys.

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