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Math Help - Super fast question about finding the mean and variance of a random variable

  1. #1
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    Question Super fast question about finding the mean and variance of a random variable

    Hi, if a problem gave you F(x) = x + 2, x > 0

    Would you derive F(x) to get f(x) in order to solve for its mean and variance?

    Thank you for your time.
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  2. #2
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    Re: Super fast question about finding the mean and variance of a random variable

    "Given F(x)= x+ 2, x> 0" doesn't mean anything! What is F supposed to be? It can't be a probability function because it has values larger than 1 and it can't be a probability density because its integral has values larger than 1.
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  3. #3
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    Re: Super fast question about finding the mean and variance of a random variable

    Sorry I wrote up an example function without really thinking.

    How about this probability distribution function?

    F(x) = 1 - x , x> 0
    Last edited by florx; October 27th 2012 at 05:00 PM.
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