Is it possible to use production data to see if the measurement equipment is measuring correctly? My company has several machines that make small round parts. Typically the diameter of the parts is within a normal distribution. So if I use hypothesis testing for mean and I see the mean of the production data is changing could that be an indication that the measurements are drifting? Therefore there is something wrong with the measurement equipment? For this to work how would I set this up? Could I compare historical data on a given manufacturing machine to new data from the same machine (Z-test)?