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Re: Prob of flipping coin n times, at no time with #h > #t?
Posted:
Feb 6, 2013 9:16 AM


On 06/02/2013 13:42, JohnF wrote: > What's P_n, the prob of flipping a coin n times, > and at no time ever having more heads than tails? > There are 2^n possible ht... sequences of n flips, > comprising a binomial tree (or pascal's triangle), > with 5050 prob of going left/right at each node. > So, equivalently, how many of those 2^n paths never > cross the "center line" (#h = #t okay after even number > of flips)?
See the ballot theorem:
http://en.wikipedia.org/wiki/Ballot_theorem



