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Thread: expectation and variance

  1. #1

    Thread Starter
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    Feb 2006
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    12

    expectation and variance

    Hi can anyone help me with this question

    A sequence of identicak and independent benoulli trials, each with probability p of success, is performed. Let the random variable X be the number of trials up to and including the nth success.

    By expressing X as a sum of geometricrandom variables, or otherwise, find the expectation and variance of X.

  2. #2
    Lively Member
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    Dec 2005
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    middle earth
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    Re: expectation and variance

    I guess we can use Binomial distribution.(check?)

    Expectation = np
    Variance=np(1-p)

  3. #3

    Thread Starter
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    Join Date
    Feb 2006
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    12

    Re: expectation and variance

    i dont think so.

    any other ideas?

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