Question 984665: In 2009, Apple’s share of laptops and desktops priced above $1000 and sold in US retail outlets was 89%. Answer the following questions based on a random sample of seven laptops and desktops priced above $1000:
What is the probability that less than five of the computers were produced by Apple?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Can look at probability 5,6,7 were Apple and take the complement, since this is dichotomous (it is either Apple or it isn't). Because fewer than 5/7 (71%) is being looked at, I would expect a low probability.
P(5)=7C5(0.89^5)(0.11^2)=0.1419
P(6)=7C6(0.89^6)(0.11)=0.3827
P(7)=0.89^7=0.4423
These add to 0.9669
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The probability that fewer than 5 computers were produced is 1-0.9669=0.0331.
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