Im trying to get my head around the relationship between the PPK for continuous data and the ability to make a Confidence and reliability statement when using a certain amount of samples to perform your testing. As an example if you wanted to make a 95%/99% CR statement and you observed that a Pre-PQ observation was a PPK of 1.09, then as per a table this allows you to choose 80 samples and as long as you get a PPK of>= 0.92 you can then make 95/99 claim. The table gives several examples using a Pre_PQ observed value so you pick the One in the table which is closest to your observed value and lower (1.05 is close and lower than 1.09).
Ive being scouring the web to find an explanation of this but have had no luck. Can any of you point me in the right direction.?
Thank you.
Ive being scouring the web to find an explanation of this but have had no luck. Can any of you point me in the right direction.?
Thank you.
Pre-PQ observed Ppk (95% confidence lower bound) | Sample Size | Acceptance Criteria | LTPD0.05 |
Ppk≥1.13 | n=50 | Ppk≥ 0.96, Pp≥ 1.02 | ≤ 1% |
Ppk≥1.11 | n=60 | Ppk≥ 0.95, Pp≥ 1.01 | ≤ 1% |
Ppk≥1.05 | n=80 | Ppk≥ 0.92, Pp≥ 0.99 | ≤ 1% |
Ppk≥1.02) | n=100 | Ppk≥ 0.90, Pp≥ 0.97 | ≤ 1% |