ASQ S3

Abstract

<strong>Scope and purpose</strong> <br>This standard describes the process of chain sampling, the theory, applications, plans for use, operating (performance) characteristics, and the utility of chain sampling as compared to single sampling via the operating characteristics. The purpose of this standard is to provide the procedures for a collection of sample sizes as well as to present the static operating characteristics for the plans presented, for use of the chain sampling technique. There is no direct indexing of the plans such as that of acceptance quality limit (AQL) used in ANSI/ASQ Z1.4 and ANSI/ISO/ASQ 2859-1. However, the complete OC are presented in both table and OC curve form for every sample size included. Furthermore, formulations are provided to compute the average outgoing quality limit (AOQL) for any of the chain sampling plans presented, related to the five values of the parameter, i, the sample size, n, and the lot size N, being applied. Those interested in using chain sampling to replace attribute sampling plans indexed either by AQL or limiting quality level (LQL) as given in ANSI/ASQ Z1.4 and ANSI/ISO/ASQ 2859-1, may select an appropriate plan from this standard by consulting the table of operating characteristics for the various sample sizes to find a plan with p at the desired AQL with probability of acceptance (Pa) equal to 0.95, 0.98, etc and/or the desired LQL at Pa equal to 0.10, Table 1 is also given herein that summarizes the p₀,₉₅ and the p_0,10 values for combinations of the parameters, n and i, to assist with this possible interest.