What Do Control Charts Look Like?
All control charts have four major
An area of the control chart that is often
overlooked is the Comments section.
All control chart
graphs have a centerline and upper and lower control limits.
The centerline represents the process mean, or grand average,
for the process.
The upper and lower control limits show the
extents of the common cause variation in the process. They
approximate plus and minus three standard deviations from the