SOLUTION: A survey of 12 people at a bookstore showed that five had purchased a hardcover book. If seven people are selected at random, what is the probability that four of them had purchase

Question 268513: A survey of 12 people at a bookstore showed that five had purchased a hardcover book. If seven people are selected at random, what is the probability that four of them had purchased a hardcover book?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A survey of 12 people at a bookstore showed that five had purchased a hardcover book. If seven people are selected at random, what is the probability that four of them had purchased a hardcover book?
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Binomial Problem:
n = 7 ; p = 5/12 ; x = 4
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P(x=4) = 7C4(5/12)^4*(7/12)^3 = 0.2094
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Cheers,
Stan H.
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