Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/5/84; site gloria.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!rochester!rocksanne!sunybcs!gloria!colonel
From: colonel@gloria.UUCP (Col. G. L. Sicherman)
Newsgroups: net.math
Subject: Re: More Heads than Tails
Message-ID: <830@gloria.UUCP>
Date: Thu, 13-Jun-85 11:59:11 EDT
Article-I.D.: gloria.830
Posted: Thu Jun 13 11:59:11 1985
Date-Received: Tue, 18-Jun-85 00:12:26 EDT
References: <239@ihnet.UUCP>
Distribution: net
Organization: SUNY-Buffalo Computer Sci.
Lines: 14

[% dead cockatrice]

> 	Suppose you have a counter, initialized to 0.
> Flip a fair coin N times, incrementing the counter whenever the coin
> comes up heads, and decrementing the counter whenever the coin comes up tails.
> What is the probability that the counter never dipped below 0.
> N	1	2	3	4	5	6	7	8
> odds	1/2	2/4	3/8	6/16	10/32	20/64	35/128	70/256

By inspecting the table, it's C(n, n div 2)/2^n.  There's
probably a simple proof.
-- 
Col. G. L. Sicherman
...{rocksvax|decvax}!sunybcs!colonel