Drexel dragonThe Math ForumDonate to the Math Forum


Math Forum
 Ask Dr. Math
 Discussions
 Internet Newsletter
 MathTools
 Problems of the Week
 Teacher2Teacher
 Teacher Exchange
 Workshops

Search All of the Math Forum:
Browse our Internet Mathematics Library

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math.independent

Topic: Prob of flipping coin n times, at no time with #h > #t?
Replies: 10   Last Post: Feb 14, 2013 2:25 AM

Advanced Search
Reply to this Topic Reply to this Topic

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Robin Chapman

Posts: 83
Registered: 5/29/08
Re: Prob of flipping coin n times, at no time with #h > #t?
Posted: Feb 6, 2013 9:16 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

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 h-t-... sequences of n flips,
> comprising a binomial tree (or pascal's triangle),
> with 50-50 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

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2013. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.