From: Caster
Date: 12/16/2004
Time: 12:04:27 PM
Hello Stan
I have spent a lot of time on your site! It helped me a lot. I especially like the 2 point idea. It appeals to me to understand both consumer and producer risks.
I have inherited a CSP-1 plan. We x-ray castings using this plan. It was set up before my time by someone who is no longer with the company. I now have to try to justify its use to a customer.
It seems to me that the way we use this plan is overly “producer friendly”. It also appears to me to have a very high consumer risk. I want to determine the consumer risk for this plan. And that is a problem for me.
The copy of the standard I have is almost illegible. I can’t easily read the OC curves.
I would like to develop my own OC curve, but I don’t know what distribution this plan is based on.
I’m confused by the use of a sampling frequency instead of sample size
It seems that I first select a sampling frequency code letter based on the number of units in the production interval (Table I). For example for 501-1200 units I can select code letters A through F.
This then lets me select sampling frequency “f” from ˝ all the way to 1/10 (Table II-A).
For example if we had 750 units in the production interval at a frequency of 1/10 my sample size is 75? Can I then make an OC curve using this sample size and Poisson method?
Or do does your software handle this type of plan?
Any help is appreciated.