From: Stan Hilliard
Date: 03 May 1999
Time: 22:46:45
> How to draw OC curve for a fixed sample & AQl level ?
There are two methods that I recommend:
METHOD (1): starting with n & Ac, and
METHOD (2): starting with two points on the "desired" OC curve.
METHOD (1): Use software program TP105 for attributes. Choose "decision rule input". Enter the fixed sample size, n, and the acceptance number, Ac. If you have a Z1.4 type of AQL plan, you can get the n & Ac from there.
(You don't need to enter AQL, as all the information needed is contained in n and Ac.)
TP105 will generate OC curves as graphs and as tables. On the input screen, choose [performance curves], [OC curves], [Graph] or [Table].
METHOD (2): Choose the producer's point(AQL,1-Alpha) and the consumer's point(RQL,Beta). TP105 will calculate the whole OC curve and n and Ac. For specific information, go here(the URL is case sensitive):
http://www.samplingplans.com/modern3.htm#EVALUATE
TP105 for attributes takes the grunt-work out of developing the sampling plan. It produces both graphs and tables of the OC curve, the decision rule: n and Ac, and sequential plans if needed. You just enter Alpha, Beta, AQL, and RQL. (example: 0.05,0.05,0.02,0.091)
If you want a fancy looking OC curve, you can export the table from TP105 and import it into MS Excel to make a graph that lools like this(the URL is case sensitive):
http://www.samplingplans.com/outputbinomial.htm#OC-Curve
Sincerely, shilliard@samplingplans.com