Question 809248
p=.15, q=.85, n=9
q^9+9q^8p=.5994 Probability that less then 2 are defective.
1-.5994=.4005 the probability (with 4 decimals without rounding) that at least 2 are defective.
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9*.15=1.35 The mean number of defective light bulbs.
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Ed