This paper presents the economic design of X control charts for monitoring a critical stage of the main production process at a tile manufacturer in Greece. Two types of X-charts are developed: a chart of the Shewhart type with fixed parameters and adaptive charts with variable sampling intervals and/or sample size. Our prime motivation was to improve the statistical control scheme employed for...

On-line monitoring of process variability is strategic to achieve high standards of quality and maintain at acceptable levels the number of nonconforming items. Shewhart control charts are the simplest Statistical Process Control (SPC) procedure to achieve this goal. An efficient implementation of a control chart requires the optimal selection of its design parameters. They can be selected acco...

The statistical performance of parametric control charts is questionable when the underlying process does not follow any specified probability distribution. Nonparametric are best substitute for this situation. On other hand, ranked set sampling technique preferred over simple random because it reduces variability parameters and improves chart’s performance. This study aims to offer a nonparame...