On Turing's Formula for Word Probabilities

A. M. Turing, in a 1941 personal communication to I. J. Good, suggested a formula for estimating probabilities of words in text and, more generally, of species in a mixed population of various species. It is remarkable that Turing's formula can be obtained by significantly different statistical methods; we compare three ways to obtain it. Copyright © 1985 by The Institute of Electrical and Electronics Engineers, Inc.