perplexus.info :: Probability : Many heads

Many heads (Posted on 2004-12-13)

What is the expected number of times you must toss a (fair) coin until you get n consecutive heads?

See The Solution Submitted by e.g.

Rating: 4.3333 (3 votes)

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answer

| Comment 4 of 6 |

let E(n) denote the expected number of times (fair) coin must be tossed until n consecutive heads is obtained.

Then E(n) = 2ⁿ⁺¹ − 2.

Posted by K Sengupta on 2007-04-17 12:13:00

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