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Thread: Expected Value + Variance

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    Expected Value + Variance




    Hi guys just a quick question

    I am told i have two values which are 100 with probability of 0.8 and 1000 with probability of 0.2. Now, I know the E(X) is just 100(.8) + 1000 (.2).

    I know my var(x) = e(x^2) - e(x)^2

    so is my var(x) just 100^2(.8) and 1000^(.2) ?

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    Re: Expected Value + Variance


    E(x^2)-E(x)^2 = [100^2(.8)+1000^2(.2)] - [(100(.8)+1000(.2))^2]
    "I have discovered a truly remarkable proof of this theorem which this margin is too narrow to contain." Pierre de Fermat

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