The Standard S Control Chart with Run Rules

The application of standard |s| control chart with two run rules in control of process variability is discussed in this paper. The control limits and average run length(ARL) are computed by the method of Markov chain. The results show that the standard |s| control chart with run rules has smaller ARL than the standard |s| control chart for all kinds of magnitudes of shifts. In the end, an example accompanied by simulation is used to illustrate that the chart with run rules is more sensitive to shifts in the process variability.