ISO 28801:2011 生产方风险质量（PRQ）和使用方风险质量（CRQ）指数化、带有最小样本量属性的二重抽样方案

标准编号：ISO 28801:2011

中文名称：生产方风险质量（PRQ）和使用方风险质量（CRQ）指数化、带有最小样本量属性的二重抽样方案

英文名称：Double sampling plans by attributes with minimal sample sizes, indexed by producer's risk quality (PRQ) and consumer's risk quality (CRQ)

发布日期：2011-03

标准范围

ISO 28801:2011为大量离散项目的验收提供了按属性的双重抽样计划。计划由生产者风险质量（PRQ）和消费者风险质量（CRQ）编制索引，其中名义生产者和消费者风险分别为（5%，5%），（5%，10%）或（10%，10%）。提供了不合格品百分比检查和每100项不合格品检查计划。如果第一个随机样本中没有不合格项（不合格），则该批次被接受，如果该批次包含两个或两个以上不合格项（不合格），则该批次被拒绝。如果在第一个样本中恰好发现一个不合格项，则抽取第二个随机样本；如果第二个样品不含不合格品（不合格品），则该批次被接受，否则将被拒收。ISO 28801:2011的目标是提供程序，以便在质量特别好或特别差时，快速、经济地确定批次处理。对于中等质量，抽取第二个样本，以便能够更可靠地区分可接受和不可接受的批次。选择这两个样本量是为了在不超过标称风险的情况下，将进料质量方面的最大预期样本量降至最低。类似地，这些计划可用于检验批次或过程质量水平等于PRQ（即可接受）的假设，以及质量水平等于CRQ（即不可接受）的替代假设。在检验成本较高、可能需要第二个样本造成的延迟和不确定性无关紧要、且消费者风险质量与生产者风险质量的比例相对较大的情况下，这些计划优于单一抽样计划。该计划适用于单独批次或短系列批次，其中两个样本大小之和不大于批次大小的约10%。当对不符合验收标准的批次进行100%检查，并将所有不合格项替换为合格项时，该计划也适用于连续系列批次；然而，对于连续系列的批次，还应考虑使用ISO 2859-1中的双重抽样计划。计划、表格和数字的统计理论见附件A。

ISO 28801:2011 provides double sampling plans by attributes for the acceptance inspection of lots of discrete items. The plans are indexed by the producer's risk quality (PRQ) and the consumer's risk quality (CRQ) where the nominal producer's and consumer's risks are respectively either (5 %, 5 %), (5 %, 10 %) or (10 %, 10 %). Plans are provided for inspection for percent nonconforming and for inspection for nonconformities per 100 items. The lot is accepted if there are no nonconforming items (nonconformities) in the first random sample, and rejected if it contains two or more nonconforming items (nonconformities). If precisely one nonconforming item is found in the first sample, a second random sample is drawn; the lot is then accepted if the second sample contains no nonconforming items (nonconformities) and rejected otherwise.The objective of ISO 28801:2011 is to provide procedures that enable lot disposition to be determined quickly and economically if quality is particularly good or bad. For intermediate quality, a second sample is drawn in order to be able to discriminate more reliably between acceptable and unacceptable lots. The two sample sizes are chosen to minimize the maximum expected sample size with respect to incoming quality subject to the nominal risks not being exceeded.Similarly, the plans may be used to test the hypothesis that a lot or process quality level is equal to the PRQ (i.e. acceptable) against the alternative hypothesis that the quality level is equal to the CRQ (i.e. unacceptable).The plans are preferable to single sampling plans where the cost of inspection is high, where the delay and uncertainty caused by the possible requirement for second samples is inconsequential and where a relatively large ratio of the consumer's risk quality to the producer's risk quality can be tolerated.The plans are suitable for isolated lots or for short series of lots, where the sum of the two sample sizes is no larger than about 10 % of the size of the lot. The plans are also suitable for continuing series of lots when lots that fail to satisfy the acceptance criteria are 100 % inspected and all nonconforming items replaced by conforming items; however, for continuing series of lots, consideration should also be given to using double sampling plans from ISO 2859-1.The statistical theory underlying the plans, tables and figures is provided in Annex A.

标准预览图