1.1 本规程建立了D19水委员会适用试验方法的测量不确定度计算标准。该实践没有提供整个工作范围的单点估计，而是将不确定性与浓度联系起来。数据分析中采用了回归统计技术。 1.2 适用的测试方法是那些其结果来自基于回归的方法，并且其数据是实验室内的数据（不是实验室间数据，例如循环研究的结果）。对于使用这种方法进行的每次分析，假设引入了固定的、可重复的样品量。 1.3 测量不确定度的计算涉及对收集的数据进行分析，以帮助在适当的浓度范围内表征分析方法。数据来源示例包括:( 1. )校准研究（可能在纯溶剂中进行，也可能不在纯溶剂中进行）( 2. )回收研究（通常在基质中进行，包括所有样品制备步骤），以及( 3. )收集作为方法持续质量控制计划一部分获得的数据。数据中可能反映或不反映使用多个仪器、多个操作员或两者，以及现场采样协议。 1.4 在任何设计的研究中，其数据将用于计算方法不确定性，用户应仔细考虑该研究试图实现的目标，并应将许多变化纳入研究中。设计研究（例如，校准、回收）的一般指导见 附录X1 . 关于变异来源的详细指南不在本实践范围内，但需要考虑的一般要点包括在 附录X2 ，但并非详尽无遗。在任何研究中，用户必须仔细考虑进行分析所涉及的因素，并且必须认识到计算的测量不确定度将反映输入数据的质量。 1.5 与测量不确定性相关的是用户选择的统计置信度。 1.6 在工作范围内的任何浓度下，测量不确定度为与回归线相关的预测区间的一半宽度。 1.7 假设用户可以访问用于执行回归的统计软件包。如果在选择此类计划时需要帮助，则应咨询统计学家。 1.8 如果正在考虑数据转换，还应咨询统计学家。 1.9 本标准并非旨在解决与其使用相关的所有安全问题（如有）。 本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.10 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 适当应用该实践应导致对测试的估计- 方法的不确定度（在工作范围内的任何浓度下），可与数据质量目标进行比较，以确定不确定度是否可接受。 5.2 通过比较回收浓度与真实浓度的数据集，得出的回归图允许将回收数据校正为真实值。此类更正的报告由用户自行决定。 5.3 在测量不确定度对数据使用很重要的情况下，本规程应用于评估测试方法的任何应用的测量不确定度。

1.1 This practice establishes a standard for computing the measurement uncertainty for applicable test methods in Committee D19 on Water. The practice does not provide a single-point estimate for the entire working range, but rather relates the uncertainty to concentration. The statistical technique of regression is employed during data analysis. 1.2 Applicable test methods are those whose results come from regression-based methods and whose data are intra-laboratory (not inter-laboratory data, such as result from round-robin studies). For each analysis conducted using such a method, it is assumed that a fixed, reproducible amount of sample is introduced. 1.3 Calculation of the measurement uncertainty involves the analysis of data collected to help characterize the analytical method over an appropriate concentration range. Example sources of data include: ( 1 ) calibration studies (which may or may not be conducted in pure solvent), ( 2 ) recovery studies (which typically are conducted in matrix and include all sample-preparation steps), and ( 3 ) collections of data obtained as part of the method’s ongoing Quality Control program. Use of multiple instruments, multiple operators, or both, and field-sampling protocols may or may not be reflected in the data. 1.4 In any designed study whose data are to be used to calculate method uncertainty, the user should think carefully about what the study is trying to accomplish and much variation should be incorporated into the study. General guidance on designing studies (for example, calibration, recovery) is given in Appendix X1 . Detailed guidelines on sources of variation are outside the scope of this practice, but general points to consider are included in Appendix X2 , which is not intended to be exhaustive. With any study, the user must think carefully about the factors involved with conducting the analysis, and must realize that the computed measurement uncertainty will reflect the quality of the input data. 1.5 Associated with the measurement uncertainty is a user-chosen level of statistical confidence. 1.6 At any concentration in the working range, the measurement uncertainty is plus-or-minus the half-width of the prediction interval associated with the regression line. 1.7 It is assumed that the user has access to a statistical software package for performing regression. A statistician should be consulted if assistance is needed in selecting such a program. 1.8 A statistician also should be consulted if data transformations are being considered. 1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Appropriate application of this practice should result in an estimate of the test-method’s uncertainty (at any concentration within the working range), which can be compared with data-quality objectives to see if the uncertainty is acceptable. 5.2 With data sets that compare recovered concentration with true concentration, the resulting regression plot allows the correction of the recovery data to true values. Reporting of such corrections is at the discretion of the user. 5.3 This practice should be used to estimate the measurement uncertainty for any application of a test method where measurement uncertainty is important to data use.