Design and Analysis of Control Charts for Standard Deviation with Estimated Parameters
نویسندگان
چکیده
منابع مشابه
The Mean and Standard Deviation of the Run Length Distribution of X̄ Charts When Control Limits Are Estimated
Control charts with estimated control limits are widely used in practice. Common practice in control chart theory is to estimate the control limits using data from the process and once the process is determined to be in control to treat the resulting control limits as though fixed. Little is known about the run length distributions of these charts when the fact that control limits are estimated...
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Control charts are one of the most important tools in statistical process control that lead to improve quality processes and ensure required quality levels. In traditional control charts, all data should be exactly known, whereas there are many quality characteristics that cannot be expressed in numerical scale, such as characteristics for appearance, softness, and color. Fuzzy sets theory is a...
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Exponential CUSUM charts are used in monitoring the occurrence rate of rare events because the interarrival times of events for homogeneous Poisson processes are independent and identically distributed exponential random variables. In these applications, it is assumed that the exponential parameter, i.e. the mean, is known or has been accurately estimated. However, in practice, the in-control m...
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The EWMA chart for the standard deviation is a useful tool for monitoring the variability of a process quality characteristic. The performance of this chart is usually evaluated under the assumption of known parameters. However, in practice, process parameters are estimated from an in-control Phase I data set. A modified EWMA control chart is proposed for monitoring the standard deviation when ...
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Standard control chart practice assumes normality and uses estimated parameters. Because of the extreme quantiles involved, large relative errors result. Here simple corrections are derived to bring such estimated charts under control. As a criterion, suitable exceedance probabilities are used.
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ژورنال
عنوان ژورنال: Journal of Quality Technology
سال: 2011
ISSN: 0022-4065,2575-6230
DOI: 10.1080/00224065.2011.11917867