SOLUTION: 20 percent of people who enter store buy something. suppose 3 people enter the store. what is the probability of at least one sale?

Question 227207: 20 percent of people who enter store buy something. suppose 3 people enter the store. what is the probability of at least one sale?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
20 percent of people who enter store buy something. suppose 3 people enter the store. what is the probability of at least one sale?
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That is a binomial problem with n=3, p = 0.20, 1<=x<=3
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P(at least one) = 1 - P(no sales in 3)
= 1 - 3C0(0.20)^0*(0.80)^3 = 1- 0.8^3 = 1- 0.5120 = 0.4880
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Cheers,
Stan H.
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