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Hello all:
Thank you everyone for making this forum such a great place to exchange knowledge.
Today I have a question that is blocking me at work. It's about sampling statistics.
We receive some parts from our supplier. The supplier is supposed to have checked the parts 100% before shipping. The final objective is that we do not want to check again at our incoming inspection.
However, the issue is that we have no garantee that the parts are not damaged during transportation. So we would like to have that proof...
We received a batch of 150 parts and we checked all of them. We found 1 NG part.
We're about to receive more shipments (around 4000 parts each).
My question is: how to prove statistically that the received parts are good with a confidence of 99.73%?
To ask the question in a different way: knowing that we found 1/150 bad part, how many parts do we need to check and find GOOD to proove statistically, with a confidence of 99.73%, that all the parts received are good and that no damage occurred during trasnportation?
Please be aware that my question is about pure sample statistics. The reasoning behind considering such a decision (and not checking all the parts for example) is not subject to this discussion.
Thank you very much
Thank you everyone for making this forum such a great place to exchange knowledge.
Today I have a question that is blocking me at work. It's about sampling statistics.
We receive some parts from our supplier. The supplier is supposed to have checked the parts 100% before shipping. The final objective is that we do not want to check again at our incoming inspection.
However, the issue is that we have no garantee that the parts are not damaged during transportation. So we would like to have that proof...
We received a batch of 150 parts and we checked all of them. We found 1 NG part.
We're about to receive more shipments (around 4000 parts each).
My question is: how to prove statistically that the received parts are good with a confidence of 99.73%?
To ask the question in a different way: knowing that we found 1/150 bad part, how many parts do we need to check and find GOOD to proove statistically, with a confidence of 99.73%, that all the parts received are good and that no damage occurred during trasnportation?
Please be aware that my question is about pure sample statistics. The reasoning behind considering such a decision (and not checking all the parts for example) is not subject to this discussion.
Thank you very much