控制图 第6部分：过程均值的 EWMA 控制图

[中文适用范围]： 本文件介绍最初由 Roberts (1959)[16] 提出的 EWMA 控制图，它是一种统计过程控制技术，用于检测过程平均值的微小偏移。它使得更快地检测到过程平均值的微小到中等偏移成为可能。在该图中，过程平均值以所有先前观测值或平均值的指数加权移动平均值的形式进行评估。在以下情况下，EWMA 控制图非常有用 - 生产率较低， - 必须检测到过程平均值的微小或中等偏移， - 抽样和检验程序复杂且耗时， - 测试成本高昂，以及 - 涉及安全风险。注：EWMA 控制图适用于变量和属性数据。给出的示例说明了这两种类型（见 5.5、附件 A、附件 B 和附件 C）。 [外文原描述]： This document covers EWMA control charts, originally proposed by Roberts (1959 )[ 16 ] , as a statistical process control technique to detect small shifts in the process mean. It makes possible the faster detection of small to moderate shifts in the process mean. In this chart, the process mean is evaluated in terms of exponentially weighted moving average of all previous observations or averages. The EWMA control chart’s application is worthwhile in particular when — production rate is slow, — a minor or moderate shift in the process mean is vital to be detected, — sampling and inspection procedure is complex and time consuming, — testing is expensive, and — it involves safety risks. NOTE EWMA control charts are applicable for both variables and attributes data. The given examples illustrate both types (see 5.5, Annex A, Annex B and Annex C).