ISO 2859-4:2020 计数检查的抽样程序 第4部分：规定质量水平的评价程序

标准编号：ISO 2859-4:2020

中文名称：计数检查的抽样程序 第4部分：规定质量水平的评价程序

英文名称：Sampling procedures for inspection by attributes — Part 4: Procedures for assessment of declared quality levels

发布日期：2020-06

标准范围

本文件建立了一致性测试的单一抽样计划，即评估相关审核群体（批次、工艺、库存、文件等）的质量水平是否符合申报值。提供了与四个级别的辨别能力相对应的抽样计划。给出了每个抽样计划的极限质量比（LQR）（见第4条）以供参考。对于I-III级，设计了抽样计划，以获得与正确申报质量水平相矛盾的风险不超过5%。未能反驳与LQR相关的错误声明的质量水平的风险不超过10%。0级样本量的设计方式是抽样计划的LQR因子与I级的LQR因子兼容。与ISO 2859系列其他部分的程序不同，本文件中的程序不适用于批次验收评估。一般来说，本文件主要关注控制I型误差，这与平衡验收抽样程序中的风险不同。本文件可用于各种形式的质量检验，在这种情况下，通过检验样品的方式提供符合某一声明质量水平的客观证据。这些程序适用于允许从实体中随机抽取单个项目样本的批次、工艺输出等实体。本文件中提供的抽样计划适用于但不限于多种目标的检查，例如:-最终项目；-部件和原材料；-业务；-在制品；-储存的用品；-维修作业；-数据或记录；-行政程序；-会计程序或会计分录；-内部控制程序。本文档考虑了离散项目和总体的两种质量模型，如下所示。i)合格-不合格模型，其中每个项目被分类为合格或不合格，并且其中项目群体的质量指标是不合格项目的比例p，或者等效地，不合格项目的百分比100 p。ii)不合格模型，其中对每个项目的不合格数量进行计数，并且其中项目群体的质量指标是在群体中的项目上发现的不合格的平均数λ，或者等价地，在群体中的项目上不合格的100 λ的百分比。

This document establishes single sampling plans for conformance testing, i.e., for assessing whether the quality level of a relevant audit population (lot, process, inventory, file etc) conforms to a declared value. Sampling plans are provided corresponding to four levels of discriminatory ability. The limiting quality ratio (LQR) (see Clause 4) of each sampling plan is given for reference. For levels I-III, the sampling plans have been devised so as to obtain a risk no more than 5 % of contradicting a correct declared quality level. The risk of failing to contradict an incorrectly declared quality level which is related to the LQR is no more than 10 %. The sample sizes for level 0 are designed in a way that the LQR factors of the sampling plans are compatible with the LQR factors for level I.In contrast to the procedures in the other parts of the ISO 2859 series, the procedures in this document are not applicable to acceptance assessment of lots. Generally, this document mainly focuses on controlling type I error, which differs from the balancing of the risks in the procedures for acceptance sampling.This document can be used for various forms of quality inspection in situations where objective evidence of conformity to some declared quality level is to be provided by means of inspection of a sample. The procedures are applicable to entities such as lots, process output, etc. that allow random samples of individual items to be taken from the entity.The sampling plans provided in this document are applicable, but not limited, to the inspection of a variety of targets such as:— end items;— components and raw materials;— operations;— materials in process;— supplies in storage;— maintenance operations;— data or records;— administrative procedures;— accounting procedures or accounting entries;— internal control procedures.This document considers two types of quality models for discrete items and populations, as follows.i) The conforming-nonconforming model, where each item is classified as conforming or nonconforming, and where the quality indicator of a population of items is the proportion p of nonconforming items, or, equivalently, the percentage 100 p of nonconforming items.ii) The nonconformities model, where the number of nonconformities is counted on each item, and where the quality indicator of a population of items is the average number λ of nonconformities found on items in the population, or, equivalently, the percentage 100 λ of nonconformities on items in the population.

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