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From: hes@ecsvax.UUCP (Henry Schaffer)
Newsgroups: net.math
Subject: Re: Combinatorics, Flipping a Coin With Restrictions
Message-ID: <1457@ecsvax.UUCP>
Date: Tue, 11-Jun-85 16:47:57 EDT
Article-I.D.: ecsvax.1457
Posted: Tue Jun 11 16:47:57 1985
Date-Received: Wed, 12-Jun-85 20:20:24 EDT
References: <239@ihnet.UUCP>
Organization: NC State Univ.
Lines: 11

This is a classical Random Walk problem.
The answer concerning the probability of crossing the equal
number of heads and tails ratio depends very much on whether 
the coin is symmetrical.
It is my understanding that a symmetrical coin will return
to equal numbers  again and again (although at surprisingly
long intervals) and so will always eventually cross over to
the other side.
Ref:An Intro to Probability Theory with Applications
Vol 1.  (I have the 2nd ed., copyright 1957) Chap. 3 is
titled "Coin Tossing and Random Walks"