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dipsydoodle

(42,239 posts)
1. Usually called the birthday problem.
Mon Feb 20, 2012, 05:37 PM
Feb 2012

Using 23 children in the same class you calculate the probability of none have the same birthday and then subtract that from 1.

See here for example : http://en.wikipedia.org/wiki/Birthday_problem

This looks a lot simpler to understand : http://www.agenarisk.com/resources/probability_puzzles/birthdays.shtml

From memory I first discovered this in one of Martin Gardner's articles back in the late sixties / early seventies. Either that or a book on reasonably basic probability.

Good idea of yours to post - gets the old grey cells working.

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