Stats God, you obviously have made a typo here. It should be “Stats Dog” because you certainly don’t know what you are talking about. Maybe you have some small kernel of knowledge about this subject but obviously have difficulty expressing yourself. Have your mother submit your next posting for you, o.k.?
Mis-application of the tools used in hypothesis testing and ANOVA certainly could lead a small-minded individual like yourself come to the conclusions you’ve posted. However, when taken in the context of the problem and how they are applied, the hypothesis testing and ANOVA techniques are quite powerful. Maybe you should do some research before you post.
But let’s stick to the original question, shall we? The answer to the question is whether or not the control chart requires time factors or, can the subgroups be based on categorical factors. Yes, you can subgroup on categorical factors. You would do this to determine if you have significant difference between clients, business type, etc. You might also try using a Multi-Vari chart and include the time factors to show performance.
And, pay no attention to those individuals who sometimes get onto this site and post nonsense like Stats Dog does. His point might be valid in a particular context but since he offers no further explanation, you can take it under advisement but don’t let it stop you.
Good luck.
.
