A Review and Evaluation of Statistical Process Control Methods inMonitoring Process Mean and Variance Simultaneously

Subject Areas : Design of Experiment

Ahmad Ostadsharifmemar ¹ , Seyed Taghi Akhavan Niaki ²

1 - Department of Industrial Engineering, Sharif University of Technology
2 - Department of Industrial Engineering, Sharif University of Technology

Received: 2010-02-07 Accepted : 2010-02-07 Published : 2010-02-07

Keywords: Statistical quality control, Control Chart, Simultaneous Control of Mean and Variance,

Abstract :

In this paper, first the available single charting methods, which have been proposed to detect simultaneous shifts in a single process mean and variance, are reviewed. Then, by designing proper simulation studies these methods are evaluated in terms of in-control and out-ofcontrol average run length criteria (ARL). The results of these simulation experiments show that the EWMA and EWMS methods are quite capable to detect large shifts in the means and variances. However, while the two EWMV procedures under study do not perform well, the Max-Min EWMA and Max-EWMA perform very well in all scenarios of mean and variance shifts.