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Math Help - Discrete Uniform Random Variable

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    Discrete Uniform Random Variable

    A discrete uniform random variable, X, has PMF of the form

    px(k) = {(1/b-a+1), k = a, a+1....b,
    0 otherwise}

    where a and b are two integers with a < b

    how do i sketch the PMF of X?
    how do i work out E[X]?

    Sorry about lack of LaTex Math
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  2. #2
    MHF Contributor matheagle's Avatar
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    You're placing equal probability on the numbers a, a+1,...,b.
    The mean is the 'midpoint'.
    Just add the integers from a to b and divide by the number of terms, b-a+1.
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    im sorry, i dont understand what you are saying?
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    am i not right in thinking that E[X] = \frac{1}{b-a+1} x \frac{b+a}{2}?

    as \frac{b+a}{2} would be moo of all the values k will take and \frac{1}{b-a+1} is the probability of all these values?
    Last edited by sirellwood; October 14th 2009 at 04:06 PM.
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