Measurement Resolution and the effect on test ratios

[WestCoastCal]

An often overlooked uncertainty component is measurement resolution.  Calibration software calculates this error component (as well as the cal standard error component) but it may be helpful to understand the behind the scenes action.  I have taught many people to understand the effect of resolution uncertainty with the attached.

[Mikey]

Is that French?

[CalLabSolutions]

Yes.  I have seen tests where the operator thought he had 4 to 1.  But the standard they was using did not have sufficient resolution.  When we recalculated the EMU based on A2LA's requirements they were no longer 4 to 1, and the lab had to note that on the calibrations.
Mike

[darkness63]

Just a hint, if you are actually doing the math by hand, you can skip a step and use the square-root of 12 as the divisor.