ISO/TS 17503:2015描述了交叉设计实验中平均值不确定性的估计，以及从此类实验中提取的方差的使用，并应用于其他测量结果（例如，单次观察）。 ISO/TS 17503:2015涵盖了任意级别的平衡双因素设计。所涵盖的基本设计包括无复制的双向设计和有复制的双向设计，其中一个或两个因素被视为随机因素。给出了方差分析表中方差分量的计算及其在不确定性估计中的应用。此外，还简要介绍了如何使用软件中的受限最大似然估计，以及如何处理具有少量缺失数据点的实验。 提供了异常值和近似正态性数据的审查方法。 包括使用通过处理相对观察（例如，分析化学中的表观回收率）获得的数据。

ISO/TS 17503:2015 describes the estimation of uncertainties on the mean value in experiments conducted as crossed designs, and the use of variances extracted from such experiments and applied to the results of other measurements (for example, single observations). ISO/TS 17503:2015 covers balanced two-factor designs with any number of levels. The basic designs covered include the two-way design without replication and the two-way design with replication, with one or both factors considered as random. Calculations of variance components from ANOVA tables and their use in uncertainty estimation are given. In addition, brief guidance is given on the use of restricted maximum likelihood estimates from software, and on the treatment of experiments with small numbers of missing data points. Methods for review of the data for outliers and approximate normality are provided. The use of data obtained from the treatment of relative observations (for example, apparent recovery in analytical chemistry) is included.