An EWMA control chart for monitoring the mean of skewed populations using weighted variance

This paper discusses the use of weighted variance (WV) in setting up the limits of the exponentially weighted moving average (EWMA) chart for the monitoring of the mean of a process from a skewed population. This chart, called the WV-EWMA chart hereafter, reduces to the standard EWMA chart when the...

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Bibliographic Details
Published in2008 IEEE International Conference on Industrial Engineering and Engineering Management pp. 218 - 223
Main Authors Khoo, M., Atta, A.
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.12.2008
Subjects
Chemical processes
Condition monitoring
Control charts
Cutting tools
Distributed computing
Equations
Error correction
EWMA chart
Gaussian distribution
Random variables
skewed populations
skewness correction
Type-I error
Type-II error
weighted standard deviation
weighted variance
X̄ chart
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Summary:This paper discusses the use of weighted variance (WV) in setting up the limits of the exponentially weighted moving average (EWMA) chart for the monitoring of the mean of a process from a skewed population. This chart, called the WV-EWMA chart hereafter, reduces to the standard EWMA chart when the underlying distribution is symmetric. The Type-I and Type-II errors of the WV-EWMA chart are compared with that of the existing charts for skewed populations. Simulation results show that the new method gives a considerable improvement over the existing methods when the underlying distribution is skewed.
ISBN:9781424426294
1424426294
ISSN:2157-3611
DOI:10.1109/IEEM.2008.4737863