How to draw Control Charts that ignore missing data?
Hi all. Sometimes we take a sample and test it for a number of parameters. On occasion, we don't need to test all parameters, so the data table can take the form of the layout below, whereby A or B can have missing values. When I draw control charts, the control chart leaves a space for the empty cells (per 1st chart below). Obviously, I'd much rather it looked like the 2nd chart below, whereby th...