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If you flip a fair coin 7 times, what is the probability that you will get exactly 2 tails?

 Jan 13, 2019
 #1
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This is a binomial probability

 

P(2 tails)  = C(7,2) * (1/2)^2 * (1/2)^5  =  C(7, 2) (1/2)^7  =  21 / 128

 

 

cool cool cool

 Jan 13, 2019
edited by CPhill  Jan 13, 2019

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