Question 496758
A bag contains 200 items of which 20 items are defectives.  seven items are selected at random 1 after another with replacement.  what is the probability of obtaning ...questions number 
1)no defective 
Binomial Problem with n = 7 and p(defect) = 20/200 = 1/10
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P(x = 0) = 7C0(0.1)^0*(0.9)^7 = 0.9^7 = 0.4783
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2)5 non defective
that is the same as 2 defective out of 7

P(x = 2) = 7C2(0.1)^2*(0.9)^5 = 0.1240
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Cheers,
Stan H.
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