A new control chart in contaminated data of t‐Student distribution for individual observations |
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Authors: | José Luis Alfaro Juan Fco Ortega |
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Institution: | Facultad de CC. Económicas y Empresariales de Albacete, Universidad de Castilla‐La Mancha, , 02071 Albacete, Spain |
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Abstract: | Control charts are the most popular tool for monitoring production quality. In traditional control charts, it is usually supposed that the observations follow a multivariate normal distribution. Nevertheless, there are many practical applications where the normality assumption is not fulfilled. Furthermore, the performance of these charts in the presence of measurement errors (outliers) in the historical data has been improved using robust control charts when the observations follow a normal distribution. In this paper, we develop a new control chart for t‐Student data based on the trimmed T2 control chart () through the adaptation of the elements of this chart to the case of this distribution. Simulation studies show that a control chart performs better than T2 in t‐Student samples for individual observations. Copyright © 2012 John Wiley & Sons, Ltd. |
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Keywords: | statistical quality control multivariate control chart t‐Student distribution trimmed estimators |
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