1.1 本规程涵盖了从其他两种具有精度限制的方法计算值时计算精度限制的技术。 1.2 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和健康实践，并确定监管限制的适用性。 ====意义和用途====== 4.1 通过对其他两个具有有效精度限制的测试结果进行加法、减法、乘法或除法计算得出的测试结果的精度限制可以直接计算。这节省了进行实验室间研究的成本和延迟。 4.2 统计理论的核心是随机变量的频率分布概念。 随机变量的精度极限由变量的标准差确定。只要单个变量独立且标准差相对于其平均值较小，则可以简单地计算随机变量的标准差，即其他两个随机变量的和、差、积或商。这些限制通常在ASTM方法中得到满足。在不满足这些限制的情况下，可以使用其他方法。本标准仅涵盖符合限制的情况。

1.1 This practice covers techniques for calculating precision limits when values are calculated from two other methods having precision limits. 1.2 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 4.1 Precision limits for a test result that is calculated by addition, subtraction, multiplication, or division of two other test results that have valid precision limits can be calculated directly. This saves the cost and delay of conducting an interlaboratory study. 4.2 At the heart of statistical theory is the concept of a frequency distribution of a random variable. The precision limit of the random variable is determined by the standard deviation of the variable. The standard deviation of a random variable that is the sum, difference, product, or quotient of two other random variables can be calculated simply so long as the individual variables are independent and the standard deviations are small relative to their mean values. These restrictions are usually met in ASTM methods. In those cases where these restrictions are not met, other methods can be used. Only cases complying with the restrictions are covered in this standard.