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Homework Help: Uniform random variable

  1. Oct 25, 2011 #1
    Let X and Y be independent and uniform on {1, 2, ... M}
    Find P(X > Y)

    so i know that P(X = x) = 1/M and P(Y = y) = 1/M
    i don't understand how Find P(X > Y) = (M+1)/2M
  2. jcsd
  3. Oct 25, 2011 #2

    I like Serena

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    Homework Helper

    Hi magnifik! :smile:

    Suppose M=3.

    Then we have the matrix:
    Code (Text):
    X\Y   1  2  3
    1     ≥
    2     ≥  ≥
    3     ≥  ≥  ≥
    In how many cases is the condition satisfied?
    And what is the total number of cases?
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