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Probabilty question !

  1. Aug 7, 2010 #1
    probabilty question plz help!

    i need full working out process...
    thanks for helping me :)
    1. Let X be a random variable with PMF
    x 0 1 2 3 4
    p(x) 5k 4k 3k 2k k

    (a) Find k.
    (b) Find E[X] and var(X).
    (c) Find E[2^X].

    2. The joint PMF of X and Y is pX;Y (x; y) = c(x2 + y2), x; y = 1; 2; 3. Find
    (a) c and the marginal PMFs of X and Y
    (b) E[X]
    (c) The PMF of 3X - 2Y
    (d) E[3X - 2Y ] in two ways.
  2. jcsd
  3. Aug 8, 2010 #2
    Re: probabilty question plz help!

    This looks like homework, and thus belongs in a homework forum (read the stickies!)

    Show us what you've attempted so far.
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