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Math Help - Random variables

  1. #1
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    Post Random variables

    Show that a Binomial (n,p) random variable is a sum of n iid Bernoulli (p) random variables???
    plz help wit dis...
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  2. #2
    Super Member Anonymous1's Avatar
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    Ok, on one condition... Never say "plz help wit dis..." again.

    Bernoulli's have mass function f(k;p) = p^k(1-p)^{1-k} for k\in \{0,1\}.

    Now, Binomial has mass function f(k;p) = {n\choose k} p^k(1-p)^{n-k} for k=1,..,n

    i.e., \sum_{k=0}^n {n\choose k} p^k(1-p)^{n-k} = (1-p)^{n} + {n\choose 1} p (1-p)^{n-1} + {n\choose 2} p^2 (1-p)^{n-2}+ ...

    What are you starting to see?

    Wait I thought of an easier way to explain this...
    Last edited by Anonymous1; March 30th 2010 at 08:20 PM.
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  3. #3
    Super Member Anonymous1's Avatar
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    Apply the Binomial theorem.

    Sorry I just got really lazy. I've been doing straight math since 9am and have been posting here on my free time. Overdose.
    Last edited by Anonymous1; March 30th 2010 at 08:17 PM.
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  4. #4
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    surely
    thank u.....
    ill try
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