Optimal Ewma control chart design using selected statistical software

Abstract

Today there are many statistical software packages wholly or partially specialized in statistical process control methods (SPC). They offer not only classical Shewhart control charts but also advanced methods suitable for non-standard situations when classical Shewhart methods fail. The ability to select the suitable control chart and insert data into the PC program is not sufficient for the effective and correct application of the selected control chart. The PC programs ask for some parameters whose optimal setting determinates correct application of the selected control chart. And information in Helps often is not sufficient. In this paper these problems are analyzed when designing optimal EWMA chart parameters using Statgraphics Plus, version 5.0.