Control of control charts

Abstract

Although the Shewhart chart is widely used in practice because of its simplicity, applying this control chart to monitor the mean of a process may lead to two types of problems. The first concerns the typically unknown parameters involved in the distribution, while the second concerns the validity of the assumption of normality itself. The objective of the research is to study and find solutions for these problems. More specifically, our goal is to determine the most suitable control chart to be used in practice. For this, subsequently, so called normal, parametric, nonparametric and combined approaches are considered, leading to corresponding control charts