94. Let N be a hypergeometric random variable having the distribution of the number of white balls in a random sample of size r from a set of w white and b blue balls.

That is, P{N = n} =

w n

 b r−n



w+b r



where we use the convention that m j

 = 0 if either j < 0 or j > m. Now, consider a compound random variable SN = N i=1 Xi , where the Xi are positive integer valued random variables with αj = P{Xi = j}.