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

Author

Khoo, Michael B C ; Atta, Abdu M A

Author_Institution

Sch. of Math. Sci., Univ. Sains Malaysia, Penang, Malaysia

fYear

2008

fDate

8-11 Dec. 2008

Firstpage

218

Lastpage

223

Abstract

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.

Keywords

control charts; moving average processes; process monitoring; statistical process control; EWMA control chart; Type-I error; Type-II error; exponentially weighted moving average control chart; skewed population; weighted variance; Chemical processes; Condition monitoring; Control charts; Cutting tools; Distributed computing; Equations; Error correction; Gaussian distribution; Random variables; EWMA chart; Type-I error; Type-II error; X̄ chart; skewed populations; skewness correction; weighted standard deviation; weighted variance;

fLanguage

English

Publisher

ieee

Conference_Titel

Industrial Engineering and Engineering Management, 2008. IEEM 2008. IEEE International Conference on

Conference_Location

Singapore

Print_ISBN

978-1-4244-2629-4

Electronic_ISBN

978-1-4244-2630-0

Type

conf

DOI

10.1109/IEEM.2008.4737863

Filename

4737863