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Math Help - random variables and variance

  1. #1
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    random variables and variance

    if we let X be a (continous or discrete) random variable with range
    Rx[-a,a]
    how can we find Var(X) which is less or equal than a^2??
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  2. #2
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    Quote Originally Posted by xixihaha View Post
    if we let X be a (continous or discrete) random variable with range
    Rx[-a,a]
    how can we find Var(X) which is less or equal than a^2??
    Please post the entire question, not just your version of it.

    Var(X) = E(X^2) - [E(X)]^2.
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  3. #3
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    that is the entire question.
    here is the exactly the question from my sheet:

    Let X be a (discrete or continuous) random variable with range Rx[-a,a]. Show that Var(X) =< a^2.
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