A Magnitude Robust Control Chart for Monitoring Process Dispersion

摘要: Several control charts have been proposed for monitoring the standard deviation of normal processes. For most process monitoring situations, the class of Shewhart control charts is typically good at detecting large changes in a process parameter while CUSUM charts are optimal for detecting changes of specific magnitudes. In this presentation we propose the use of a magnitude robust control chart for monitoring for changes in a normal process standard deviation. Our proposed control chart can be used when there is subgrouping (samples of size n greater than one) or when there is no subgrouping (individual observations, ie, samples of size n= 1). The performance of our proposed control chart is compared with that of its competitors.[PUBLICATION ABSTRACT]