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pdurrant · 06-09-2010, 04:45 PM

Here's a fun bit of probability calculation. Taken (with some changes to make me happier about the answer) from an article in the New Scientist magazine.

Dan and Nick are talking to each other. Nick has no prior knowledge of Dan or his family. Work out the probability, at each numbered stage of the conversation, that Dan has exactly two male children (BB) given the information to that stage. Assume that the probability of any child of any parent being a boy is exactly 1 in 2.

Dan: I have exactly two children
1
Nick: Do you have at least one boy?
Dan: Yes.
2
Nick: Do you have at least one boy born on a Tuesday?
Dan: Yes.
3

I'll give the answers and reasoning behind the answers after there have been some comments. I will say that the probabilities at 1, 2 and 3 are all different.

I just hope that some other people on Mobileread are also a bit geeky about probability

06-09-2010, 04:45 PM	#1
pdurrant The Grand Mouse 高貴的老鼠 Posts: 74,082 Karma: 315558332 Join Date: Jul 2007 Location: Norfolk, England Device: Kindle Oasis	Probability Fun Here's a fun bit of probability calculation. Taken (with some changes to make me happier about the answer) from an article in the New Scientist magazine. Dan and Nick are talking to each other. Nick has no prior knowledge of Dan or his family. Work out the probability, at each numbered stage of the conversation, that Dan has exactly two male children (BB) given the information to that stage. Assume that the probability of any child of any parent being a boy is exactly 1 in 2. Dan: I have exactly two children 1 Nick: Do you have at least one boy? Dan: Yes. 2 Nick: Do you have at least one boy born on a Tuesday? Dan: Yes. 3 I'll give the answers and reasoning behind the answers after there have been some comments. I will say that the probabilities at 1, 2 and 3 are all different. I just hope that some other people on Mobileread are also a bit geeky about probability Last edited by pdurrant; 06-10-2010 at 10:35 AM. Reason: Fixed the setup to make my answer correct!