If by "out of control" you mean deviant, I would agree.
Baseline is not the same as average. It is the cutting point at which you will reject the product. It would depend on the quality standards you have for your product.
An an analogy, let's use academic grades. "C" would be average, but between "D" and "F" would be my baseline for rejection.
What I mean by a "running number" is that the average is always changing. If I turn in 10 homework assignments and the grades are as follows: 58, 87, 99, 90, 92, 95, 89, 90, 95, 91 then my average is 88.6. If I turn in 10 more assignments my average changes, we don't say that my next 10 are either in control or out of control. Although, personally, I would have said the 58 was out of control from the start. At what point in a production environment does the average change? My company has a lot of returns, so if I were to start taking data I'm sure I would be calculating an average that contains parts that are below quality standards. Hopefully we would improve, but I don't know when I would create a new baseline, surely we wouldn't want the same baseline forever.
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