1.1 该实践提出了一种自动、客观的线性拟合方法，用于确定测试记录的线性部分的斜率。该方法假设在测试记录的早期存在一个线性区域，其中 y 变量大致与 x 变量，并且记录的斜率在线性区域之后减小。该实践基于最小归一化残差确定数据的最佳线性拟合，并提供用于评估测试记录的质量和结果拟合的质量的度量。 1.2 应用数据质量度量来评估噪声水平和数据的数字分辨率，以确定测试记录是否足以进行线性回归分析。 拟合质量指标使用拟合范围附近的残差分析来确定测试记录是否足够线性，拟合范围是否足够大。 1.3 对于满足数据和拟合质量指标的测试记录，该实践确定了一个可重复的斜率，而不需要独立于操作员判断的操作员输入。对于未通过一个或多个质量指标的测试记录，建议分析员评估拟合度，以确定其是否可接受。 1.4 该实践代表了一种通用方法，适用于任何需要线性拟合的测试标准或方法。当必须确定坡度时，可采用标准试验方法采用这种做法。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 通常需要确定测试记录内线性区域的斜率，并且为了标准化的目的，希望有一种非主观的确定斜率的方法。 有许多ASTM标准测试方法，其中测试程序或分析要求确定斜率，但这样做的程序没有很好地定义。理想情况下，如果多个实验室分析相同的数据来确定斜率，它们应该产生相同的结果。本标准实践的目的是消除作为测试结果可变性来源的线性拟合。

1.1 This practice presents an automated, objective linear-fitting method for determining the slope of the linear portion of a test record. The method assumes that there is a linear region early in the test record where the value of the y variable increases roughly in proportion to the x variable and the slope of the record decreases after the linear region. The practice determines the best linear fit to the data based on the least normalized residual and provides metrics for evaluating the quality of the test record and the quality of the resultant fit. 1.2 Data quality metrics are applied that evaluate the level of noise and the digital resolution of the data to determine if the test record is adequate for a linear regression analysis. Fit quality metrics use analysis of residuals in the vicinity of the fit range to determine if the test record is adequately linear and the fit range is sufficiently large. 1.3 For test records that meet the data and fit quality metrics, the practice determines a repeatable slope without the need for operator input that is independent of operator judgment. For test records that fail one or more of the quality metrics, it is recommended that the analyst evaluate the fit to determine if it is acceptable. 1.4 This practice represents a general purpose approach that is applicable for any test standard or method in which a linear fit is desired. It is intended that this practice can be called upon by standard test methods when slope must be determined. 1.5 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. 1.6 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 It is often necessary to determine the slope of a linear region within a test record, and for standardization purposes, it is desirable to have a method for determining the slope that is not subjective. There are numerous ASTM standard test methods where the test procedure or analysis requires that slope be determined, but the procedures for doing so are not well defined. Ideally, if multiple laboratories analyze the same data for determination of slope, they should produce the same result. The objective of this standard practice is to eliminate the linear-fit as a source of variability in test results.