Monitoring the Coefficient of Variation Using EWMA Charts

• Autores: Philippe Castagliola, Giovanni Celano, Stelios Psarakis
• Localización: Journal of quality technology: A quarterly journal of methods applications and related topics, ISSN 0022-4065, Vol. 43, Nº. 3, 2011, págs. 249-265
• Idioma: inglés
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• Resumen

  • This paper suggests a new method of monitoring the coefficient of variation (CV) using two-sided EWMA charts of the variation squared. Tables demonstrate the statistical properties of this method when shift size is unknown or deterministic. An example using real data from a metal sintering process demonstrates the use of the charts.