The hypergeometric distribution with parameters N, G and n is the distribution of the number of "good" objects in a simple random sample of size n (i.e., a random sample without replacement in which every subset of size n has the same chance of occurring) from a population of N objects of which G are "good." The chance of getting exactly g good objects in such a sample is

GCg × N₋GCn₋g/NCn,

provided g ≤ n, g ≤ G, and n − g ≤ N − G. (The probability is zero otherwise.) The expected value of the hypergeometric distribution is n×G/N, and its standard error is

((N−n)/(N−1))^½ × (n × G/N × (1−G/N) )^½.