The Psychology of Quality and More
Calculation detail for X-MR Control Charts
Control Charts, as described in previous articles, are used to detect statistically-significant variation in processes and hence enables variation and quality to be pro-actively controlled. There are seven types of control chart, each of which has a different calculation for the upper and lower control limits. This month, we are covering the calculations for variables charts.
Fig. 1. Calculating X/MR control limits
This article first appeared in Quality World, the journal of the Chartered Quality Institute
And the big