Thread: Estimation

I am having trouble getting the answer to this problem, i tried a few ways and have gotten .022 and .025 but the answer they want is .0301.

I don't know the method of estimation wanted, only the answer they give (again .0301)


Here is the problem:

Wafers in a plant are inspected for conformance to specifications. N=100 wafers are inspected. If the number of nonconforming wafers is no more than 12, the lot is accepted. Estimate the probability of acceptance if the proportion of nonconforming wafers in the lot is 0.2.


Thanks for the help

Originally Posted by jarny

I am having trouble getting the answer to this problem, i tried a few ways and have gotten .022 and .025 but the answer they want is .0301.

I don't know the method of estimation wanted, only the answer they give (again .0301)


Here is the problem:

Wafers in a plant are inspected for conformance to specifications. N=100 wafers are inspected. If the number of nonconforming wafers is no more than 12, the lot is accepted. Estimate the probability of acceptance if the proportion of nonconforming wafers in the lot is 0.2.


Thanks for the help

I would have used a binomial approximation to the hypergeometric distribution: The Binomial Approximation to the Hypergeometric

(which I suppose could then be approximated by a normal distribution ....)