What in math what does it mean when I'd a sample process is in control or not?

I'm not totally sure what you are asking, but maybe this is a question about dependent and independent variables?

If so, these types of variables are used in math and science as measures. In math, independent variables and dependent variables are the "tools" used in an experiment.

Independent variables are the variables that are controlled during the experiment. These variables do not change during the experiment.

Dependent variables are the variables whose values change based on the independent variables. These variables are the "outcome" portion.

I have no idea if this answers your question or not. All I can say is that the "controlled" part of a sample would be the independent variable.