I'm working on a project to draw control charts.
Ive generated output using PROC Shewhart Irchart but my variance changes significantly about 1/3rd of the way through the data.
Is there a way to have the limits self adjust when the variance changes? It looks like there may be a way of doing it in Shewhart but it is hard to tell for sure.
I've seen something about proc macontrol. I've tried copying the generated code in EG from shewhart and putting in the code for proc macontrol but so far it is not working