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 data you collect ...

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 for the X-bar and R ...

Control limits, how do they work? Is it a probability limit? Is it an economic limit? Read on to find out! A control chart consists of several parts. It has two limits. The bottom dashed line is ...