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Math Help - Proving variance formula

  1. #1
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    Proving variance formula

    How does one prove the formula: var(X) = E(X2) − E2(X)?

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  2. #2
    Super Member Random Variable's Avatar
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     \displaystyle V(X) = E(X-\mu)^2 = E(X^2 - 2 \mu X + \mu^2)

     = E(X^2) - 2 \mu E(X) + E(\mu^{2})

     = E(X^2) - 2 \mu^{2} + \mu^{2} = E(X^2) - \mu^{2}
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