Interpretation & Calculations
The upper & lower control limits for the Moving Average chart.
where n is the subgroup size, w is the moving (cell) size, σx is the process sigma based on the Moving Range chart or the Moving Sigma chart, and X-doublebar is the overall average:
m is the total number of subgroups
A Moving Range or Moving Sigma chart is used to monitor process variation.
Learn more about the SPC principles and tools for process improvement in Statistical Process Control Demystified (2011, McGraw-Hill) by Paul Keller, in his online SPC Concepts short course (only $39), or his online SPC certification course ($350) or online Green Belt certification course ($499).