The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) $\overline{X}$ scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA $\overline{X}$ scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA $\overline{X}$ scheme.

中文翻译：

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用于过程监控的混合均匀加权移动平均控制图：讨论

监测方案的敏感性取决于许多因素，包括图表统计量的方差，这在控制限的计算中非常重要。本文讨论了最近提出的混合均匀加权移动平均 (HHWMA) 的方差计算$\overline{X}$基于错误假设的方案。正确的方差用于评估 HHWMA 的游程特征$\overline{X}$方案。据观察，不正确的方差对 HHWMA 的灵敏度（或性能）有显着影响$\overline{X}$ 方案。