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Probability and expected value question...?

I conduct an experiment which consists of a series of independent trials. Each trial succeeds with probability p. X is the number of trials until we have a successful trial. Find E[X].

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  • 1 decade ago
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    q = 1 - p is the probability of failure

    probability of succeeding on trial X is q^(X-1)p

    E(X) = Sum[ x q^(x-1) p (from 1 to X)]

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