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Math Help - Expected Value of Dice

  1. #1
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    Expected Value of Dice

    Roll two dice and find E(X) and the variance of X if:

    • X is the product of the two dice
    • X is the larger of the two dice


    For b, I have

    X=1 then E(X) = 0/36
    X=2 then E(X) = 2/36
    X=3 then E(X) = 4/36
    X=4 then E(X) = 6/36
    X=5 then E(X) = 8/36
    X=6 then E(X) = 10/36

    any help?
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  2. #2
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    Quote Originally Posted by asept View Post
    Roll two dice and find E(X) and the variance of X if:

    • X is the product of the two dice
    • X is the larger of the two dice


    For b, I have
    X=1 then P(X) = 0/36
    X=2 then P(X) = 2/36
    X=3 then P(X) = 4/36
    X=4 then P(X) = 6/36
    X=5 then P(X) = 8/36
    X=6 then P(X) = 10/36
    I made corrections in your notation in red above.
    Those should be probabilities: P(X).
    Expection is E(X) = \sum\limits_{x = 1}^6 {xP(x)} .

    For the first part your outcomes 1,2,3,4,...,25,30,36.
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