B
... the reality is that Control Charts are not and never were intended to provide accurate and precise point estimates of the process performance.
in short: it doesn't matter. use one of them. Shewharts' book was entitled "the economic control of quality", not the "exactly precise accurate determination of exactly what is going on with infinite confidence in the results"
in short: it doesn't matter. use one of them. Shewharts' book was entitled "the economic control of quality", not the "exactly precise accurate determination of exactly what is going on with infinite confidence in the results"
Besides, it was more for others benefit...not much you haven't already heard from me!