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Homework Help: Flipping a coin

  1. Oct 14, 2008 #1
    1. The problem statement, all variables and given/known data If I flip a fair coin n times, that is the probability that I get k heads?

    2. Relevant equations nCk: the combination in which order doesn't matter s.t one picks k from n.

    3. The attempt at a solution there are 2*2*2*2*2.....*2=2^n total outcomes. but the event specifies k ways of picking heads out of n flips. So, (nCk)/(2^(n)). Is this correct? Intuitively, I think its sound.
  2. jcsd
  3. Oct 14, 2008 #2


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    Yes, it's quite sound.
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