标准编号：ISO 8422:2006
中文名称：项目检验用序列抽样法
英文名称：Sequential sampling plans for inspection by attributes
发布日期：2006-10
标准范围
This International Standard specifies sequential sampling plans and procedures for inspection by attributes ofdiscrete items.The plans are indexed in terms of the producer's risk point and the consumer's risk point. Therefore, they canbe used not only for the purposes of acceptance sampling, but for a more general purpose of the verificationof simple statistical hypotheses for proportions.The purpose of this International Standard is to provide procedures for sequential assessment of inspectionresults that may be used to induce the supplier, through the economic and psychological pressure of nonacceptanceof lots of inferior quality, to supply lots of a quality having a high probability of acceptance. At thesame time, the consumer is protected by a prescribed upper limit to the probability of accepting lots of poorquality.This International Standard provides sampling plans that are applicable, but not limited, to inspection indifferent fields, such as:- end items,- components and raw materials,- operations,- materials in process,- supplies in storage,- maintenance operations,- data or records, and- administrative procedures.This International Standard contains sampling plans for inspection by attributes of discrete items. Thesampling plans may be used when the extent of nonconformity is expressed either in terms of proportion (orpercent) nonconforming items or in terms of nonconformities per item (per 100 items).The sampling plans are based on the assumption that nonconformities occur randomly and with statisticalindependence. There may be good reasons to suspect that one nonconformity in an item could be caused bya condition also likely to cause others. If so, it would be better to consider the items just as conforming or not,and ignore multiple nonconformities.The sampling plans from this International Standard should primarily be used for the analysis of samplestaken from processes. For example, they may be used for the acceptance sampling of lots taken from aprocess that is under statistical control. However, they may also be used for the acceptance sampling of anisolated lot when its size is large, and the expected fraction nonconforming is small (significantly smaller than10 %).In the case of the acceptance sampling of continuing series of lots, the system of sequential sampling plansindexed by acceptance quality limit (AQL) for lot-by-lot inspection published in ISO 2859-5 should be applied.
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