Question 266372
A company manufactures calculators in batches of 45 and claims that the rate of defects is 4%. Find the probability of getting exactly 2 defects in a batch of 45 if the rate of defects is 4%.
Binomial Problem:
n = 45 ; p = 0.04 ; x=2
P(x=2) = 45C2(0.4)^2(0.96)^43 = 0.2738
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Ans: d
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If a store receives a batch of 45 calculators and finds that there are 2 defective calculators, do they have any reason to doubt the company's claimed rate of defects?
No, the probability is better than 27% that 2 defects would be found in
a batch of 45.
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Cheers,
Stan H.
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Possible answers:

a. 0.263; No. If the rate of defects is really 4%, it is not so unlikely to find 2 defects in a batch of 45 calculators. 
b. 0.548; No. If the rate of defects is really 4%, it is not so unlikely to find 2 defects in a batch of 45 calculators. 
c. 0.0166; Yes. If the rate of defects is really 4%, the probability of finding 2 defects in a batch of 45 calculators is very small. 
d. 0.274; No. If the rate of defects is really 4%, it is not so unlikely to find 2 defects in a batch of 45 calculators.