Sampling procedures for inspection by variables Part 2: General specification for single sampling plans indexed by acceptance quality limit (AQL) for lot-by-lot inspection of independent quality characteristics
|Publication Date:||1 April 2006|
|ICS Code (Application of statistical methods):||03.120.30|
This part of ISO 3951 specifies an acceptance sampling system of single sampling plans for inspection by variables, indexed in terms of the Acceptance Quality Limit (AQL).
This part of ISO 3951 is primarily designed for use under the following conditions:
a) where the inspection procedure is to be applied to a continuing series of lots of discrete products all supplied by one producer using one production process. If there are different producers or production processes, apply this part of ISO 3951 to each one separately;
b) where the quality characteristics of the items of product are measurable on a continuous scale;
c) where the measurement error is negligible (i.e. with a standard deviation no more than 10 % of the corresponding process standard deviation);
d) where production is stable (under statistical control) and the quality characteristics are distributed, at least to a close approximation, according to normal distributions;
e) where, in the case of multiple quality characteristics, the characteristics are independent of one another, at least approximately;
f) where a contract or standard defines an upper specification limit U, a lower specification limit L, or both on each of the quality characteristics.