From: Stan Hilliard
Date: 12 Sep 2001
Time: 01:56:07
Greetings Bart,
> YOU SAID -- "Does the software also contain decision rules taken into account the confidence limits ??? For example: Specification indicates that fraction f within lot: f > 97% result within sample: 96% +/- 3%"
REMARK -- TP105 will calculate, by entering the sample results (n and x), one-sided or two-sided confidence limits for percent defective -- at any % confidence that you choose from 50% to 99.9999%. You can also enter n and (n-x) to calculate the confidence limits on percent good for that lot (or group of lots).
If I understand the confidence limit requirement, a lot must be shown to be >97% good with 95 % confidence. That would mean that the lower 95% confidence limit on % good has to be equal to or higher than 97% good.
In terms of %defective -- the upper 95% confidence limit would have to be equal to or less than 3% defective (100-97). Because of the relationship between confidence limits and decision rules, the RQL(LQ) should be 3%. That is, by definition, the upper confidence limit on % defective is identical to RQL. The % confidence is (1-beta) where beta is the consumers risk. So you don't need a computer program for that!
Stan Hilliard