The drawbacks to multivariate charting schemes is their inability to identify which
variable was the source of the signal. The multivariate exponentially weighted
moving average (MEWMA) developed by Lowry, et al (1992) is an example of a
multivariate charting scheme whose monitoring statistic is unable to determine
which variable caused the signal. In this paper, the run length performance of
multivariate exponentially weighted moving average (MEWMA) chart with
application is studied. Industry fertilizers is important one of the chemical
industries in Egypt, so that this work concerns the fertilizers industries quality
control, especially urea fertilizer with application on Delta fertilizer and chemical
industries which is considered on of the leading companies the field of fertilizer
production in Middle east with application of multivariate quality control
procedures to achieve best one procedure for multivariate quality control. |
