## Quick Reference

A distribution, presented in 1951 by the Swede, Gerhard Arfwedson, concerned with the case where each observation takes one of *k* equally likely values. Let *M* be the random variable denoting the number of values that do not occur in a sample of size *n*. The distribution of *M* is given by The distribution has also been called the coupon-collecting distribution, since one application is to find the probability that a person having *n* randomly selected coupons (which might be cigarette cards, plastic toys from cereal packets, etc.) will have at least one of each of the *k* equally likely varieties.

*Subjects:*
Probability and Statistics.