Key Points X-bar and R charts are useful control charts for use with rational subgroups. X-bar measure between-sample variation. R charts measure within-sample variation. All processes vary. The ...

The control chart basics.2 types of variation and how we distinguish between common and special cause variation, along with how to create a rational subgroup. We also cover the equations and constants ...

Control chart techniques have been widely used in industries to monitor a process in quality improvement. Whenever we deal with variables data, we usually employ a combination of X-bar chart and R ...