测量的不确定性. 第4部分: 合格评定中不确定性的测量作用

[中文适用范围]： 本文件提供了评估项目（实体、对象或系统）是否符合指定要求的指南和程序。 例如，该物品可以是量块、食品秤或血液样本。 当存在以下条件时，可以应用这些程序： ——该项目通过单个标量（见 3.2.1）（可测量的属性）来区分，其细节程度足以由本质上唯一的真值合理地表示；注：GUM 提供了不使用术语“真实”的理由，但当可能存在歧义或混淆时，将在本文档中使用该术语。 - 属性允许值的区间由一个或两个容差限值指定； ——财产可以被测量，并且测量结果（见 3.2.5）以符合 GUM 原则的方式表达，以便财产价值的知识可以通过（a）概率密度函数（参见 3.1.3) (PDF)，(b) 分布函数（参见 3.1.2），(c) 此类函数的数值近似值，或 (d) 最佳估计，以及覆盖区间和相关覆盖概率。 [外文原描述]： ISO/IEC Guide 98-4:2012 provides guidance and procedures for assessing the conformity of an item (entity, object or system) with specified requirements. The item might be, for example, a gauge block, a grocery scale or a blood sample. The procedures can be applied where the following conditions exist: the item is distinguished by a single scalar quantity (a measurable property) defined to a level of detail sufficient to be reasonably represented by an essentially unique true value; an interval of permissible values of the property is specified by one or two tolerance limits; the property can be measured and the measurement result expressed in a manner consistent with the principles of the GUM, so that knowledge of the value of the property can be reasonably described by (a) a probability density function, (b) a distribution function, (c) numerical approximations to such functions, or (d) a best estimate, together with a coverage interval and an associated coverage probability. The procedures developed in this document can be used to realize an interval, called an acceptance interval, of permissible measured values of the property of interest. Acceptance limits can be chosen so as to balance the risks associated with accepting non-conforming items (consumer's risk) or rejecting conforming items (producer's risk). Two types of conformity assessment problems are addressed. The first is the setting of acceptance limits that will assure that a desired conformance probability for a single measured item is achieved. The second is the setting of acceptance limits to assure an acceptable level of confidence on average as a number of (nominally identical) items are measured. Guidance is given for their solution. This document contains examples to illustrate the guidance provided. The concepts presented can be extended to more general conformity assessment problems based on measurements of a set of scalar measurands. The audience of this document includes quality managers, members of standards development organizations, accreditation authorities and the staffs of testing and measuring laboratories, inspection bodies, certification bodies, regulatory agencies, academics and researchers.