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Math Help - initials problem

  1. #1
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    initials problem

    What is the probability that in a group of 200 people, at least 2 of them have the same initials?

    I'm finding the probability to be about .679. Is this correct?
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  2. #2
    MHF Contributor matheagle's Avatar
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    Quote Originally Posted by jmedsy View Post
    What is the probability that in a group of 200 people, at least 2 of them have the same initials?

    I'm finding the probability to be about .679. Is this correct?

    Attack this like the birthday problem.
    Look at the complement, that there are no matches at all.
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  3. #3
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    Just a caveat about real-world probabilities. (It's not clear whether this is a textbook exercise or a real-world problem.)

    In the "real world", initials are anything but uniformly distributed; there are far more S's then Z's, for example. If you want a real-world answer, you will need to find some data on the distribution of initials and take that into account.
    Last edited by awkward; May 24th 2010 at 03:00 PM. Reason: typo
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