Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 beta 3/9/83; site sdcrdcf.UUCP Path: utzoo!linus!decvax!harpo!seismo!hao!hplabs!sdcrdcf!darrelj From: darrelj@sdcrdcf.UUCP (Darrel VanBuer) Newsgroups: net.math,net.games Subject: Re: Party game of chance Message-ID: <838@sdcrdcf.UUCP> Date: Sun, 12-Feb-84 18:15:40 EST Article-I.D.: sdcrdcf.838 Posted: Sun Feb 12 18:15:40 1984 Date-Received: Wed, 15-Feb-84 06:14:52 EST References: <211@heurikon.UUCP> Reply-To: darrelj@sdcrdcf.UUCP (Darrel VanBuer) Organization: System Development Corporation, Santa Monica Lines: 14 The probability of adding the m-th person to a set of people with different birthday is (roughly) (366-m)/365 [ignores leap year, assumes all dates equally likely]. So the probabily of a set of m all different is (364 * 363 * 362 * ... 366-m)/365**(m-1). This works out to about 50% at 25 people and not quite certain at 50 people. -- Darrel J. Van Buer, PhD System Development Corp. 2500 Colorado Ave Santa Monica, CA 90406 (213)820-4111 x5449 ...{allegra,burdvax,cbosgd,hplabs,ihnp4,sdccsu3,trw-unix}!sdcrdcf!darrelj VANBUER@USC-ECL.ARPA