A random sample of size 12 is taken without replacement from a lot of 100 items that contains 8 defectives.
(a) Find the probability that there are exactly two defectives in the sample.'
(b) Find the probability that there are two or fewer defectives in the sample
Solution:
(a) In this problem, there are some 100 items out of which 8 are
defective. A sample of 12 is taken out without replacement. The
example provided in the problem is a hypergeometric one.
It is required to obtain the probability that the lot has only two
defective item. The following formula can be used:
the probability that there are exactly two defectives in the sample is 0.1922
(b) The probability that there are two or fewer defectives in the sample
The probability that there are two or fewer defectives in the sample is 0.9469
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