Title: Hotelling's T² charts with variable control and warning limits

Authors: Shashibhushan B. Mahadik

Addresses: D.R.K. College of Commerce, Kolhapur, 416002, India

Abstract: The idea of variable control and warning limits (VCWL) is proposed for Hotelling's T² charts in order to improve their performances in detecting small shifts in the mean vector. Expressions for the performance measures for VCWL T² charts are developed. The performances of these charts are compared numerically with those of static T² charts. It is observed that the VCWL T² charts are significantly more efficient than the static T² charts in detecting the small shifts and as efficient as that in detecting moderate to large shifts.

Keywords: adaptive control charts; average run length; ARL; multivariate SPC; statistical process control; Markov chain; variable control; warning limits.

DOI: 10.1504/IJQET.2012.049683

International Journal of Quality Engineering and Technology, 2012 Vol.3 No.2, pp.158 - 167

Received: 22 Feb 2012
Accepted: 10 Apr 2012

Published online: 12 Oct 2012 *

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