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Coin toss

  1. Oct 11, 2004 #1
    K people independently toss a coin n times. What is the probability that all K of them get the same number of heads?
    (1) Find a formula for the probability in terms of K and n.
    (2) Evaluate the probability for K = {5, 10, 20} and n = {4, 8, 16}
  2. jcsd
  3. Oct 11, 2004 #2
    Let me see if I remember this:


    Where P(n) is the probability that an x number of events will occur out of n number of tries. pi is the certainty (in the case of a coin with 2 sides pi=1/2). C(n,x) is: n!/((n-x)!*k!)

    Apply the formula K-1 times.
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