Question 1141739: Please help me solve this equation: Thirty percent of consumers prefer to purchase electronics online. You randomly select 8 consumers. Find the probability that the number of consumers who prefer to purchase electronics online is (a) exactly five, more than five, and (c) at most five.
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Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! Use Binomial Probability Formula
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Probability (P) (k successes in n trials) = nCk * p^k * (1-p)^(n-k), where p is the probability of success, nCk = n!/(k! * (n-k)!)
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For this problem, n = 8, p = 0.30
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(a) P(exactly 5 consumers prefer to purchase electronics online) = 8C5 * (0.30)^5 * (1-0.30)^(8-5) = 0.0467 is approximately 0.05
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(b) P(more than 5 consumers prefer to purchase electronics online) = summation from k = 6, 8 of P(k successes in 8 trials) = 0.0113 is approximately 0.01
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(c) P(at most 5 consumers prefer to purchase electronics online) = 1 - P(more than 5 consumers prefer to purchase electronics online) = 1 - 0.01 = 0.99
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