Monitoring the mean and the variance of a stationary process |
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Authors: | S. Knoth,& W. Schmid |
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Affiliation: | European University Viadrina, Department of Statistics, D-15207 Frankfurt (Oder), FRG |
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Abstract: | We deal with the problem of how deviations in the mean or the variance of a time series can be detected. Several simultaneous control charts are introduced which are based on EWMA (exponentially weighted moving average) statistics for the mean and the empirical variance. The combined X − S2 EWMA chart is extended to time series. Further simultaneous charts are considered. The comparision of these schemes shows that the residual attempt must be favored if a variance change is present. |
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Keywords: | Statistical process control EWMA charts simultaneous control charts time series |
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