SOLUTION: Suppose that a family has 8 children.​ Also, suppose that the probability of having a boy is one half . Find the probability that the family has at least 7 boys.

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Question 1137022: Suppose that a family has 8 children.​ Also, suppose that the probability of having a boy is one half
. Find the probability that the family has at least 7 boys.
Answer by greenestamps(13203) About Me  (Show Source):
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P(at least 7 boys) = P(7 boys or 8 boys) = P(7 boys) + P(8 boys)

P(8 boys) = (8C8)(1/2)^8 = 1/256
P(7 boys) = (8C7)(1/2)^8 = 8/256

P(at least 7 boys) = 9/256