RANDHYPERG(n1,n2,t)
RANDHYPERG returns a hypergeometric-distributed random number. The probability distribution for hypergeometric random variates is,
p(k) = C(n_1,k) C(n_2, t-k) / C(n_1 + n_2,k),
where C(a,b) = a!/(b!(a-b)!).
The domain of k is max(0,t-n_2), ..., max(t,n_1).
RANDHYPERG(21,1,9).
RAND.