Question 176625
A business owner decides to use a binomial distribution to solve one of his problems. He knows there is a 60 percent probability that he will sell one of his Red Oak floors to any customer who comes into his shop and views the wood. Out of the next 7 people who come into his shop, 
what is the probability that 3 people will buy a Red Oak floor? ___________ 
Using a TI calculator I get binompdf(7,0.6,3) = 0.1935..
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What is the probability that more than four people will buy the Red oak floor? 
1 - binomcdf(7,0.6,4) = 0.4199...
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Alternate solution:
P(4 < x < 7) = P(x=5) + P(x=6) + P(x=7)
= 7C5(0.6)^5(0.4)^2 + 7C6(0.6)^6(0.4) + 7C7(0.6)^7(0.4)^0

= 21*0.07776*0.16 + 7*0.04665*0.4 + 1*0.02799

= 0.26127 + 0.13062 + 0.02799

= 0.41988...
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Cheers,
Stan H.

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Cheers,
Stan H.