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Homework Help: Confusing Ball Problem.

  1. Feb 24, 2010 #1
    hey, im having a lot of trouble approaching this problem:

    let m balls be independently distributed into s boxes with equal probabilities
    m has a poisson distribution with mean 1/b
    let Xi be the number of balls in box i, i = 1,2,...,s
    let y = the number of empty boxes
    are X1, X2, ... , Xs independent?

    i cant really conceptualize a function to describe the Xi's and cant find the joint pdf of X1,X2,...Xs

    my thought was that p(Xi) = (1/s)^(Xi) * ((s-1)/s)^(m - Xi)
    but, i don't see how that gets anywhere...

    i would appreciate any advice!
    Last edited: Feb 24, 2010
  2. jcsd
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