This part of ISO 3951 establishes sampling plans and procedures by variables that can be used to assesswhether the quality level of an entity (lot, process, etc) conforms to a declared value. The sampling plans havebeen devised so that their operating characteristic curves match those of the corresponding attributes plans inISO 2859-4 as closely as possible, so that the choice between using sampling by attributes and sampling byvariables is not influenced by attempts to increase the chance of accepting an incorrectly declared qualitylevel. In this part of ISO 3951, there is a risk of between 1,4 % and 8,2 % of contradicting a correct declaredquality level.
DS/ISO 3951-4:2011 history
2011DS/ISO 3951-4:2011 Sampling procedures for inspection by variables - Part 4: Procedures for assessment of declared quality levels