We are manufacturing a device with a plastic coating on a lens with thickness specification of 42 microns +/6 and we have a maximum allowed spread of 6 microns.
Data values taken at 4 points might be 42, 39, 41, 36. The spread (or precision per the "standard" below) of these values is 6.
The only measuring device we have currently has a repeatability and accuracy of +/ 1.5 microns. For determining how much error this device takes up from the thickness specification I think its just 12/3 which is 25% of that +/6 tolerance. For the precision range would that be calculated the same resulting in 50%?
I am posting an ISO standard since I am trying to use standard definitions which seem to vary quite a bit  "trueness" instead of "accuracy" for example.
https://en.wikipedia.org/wiki/Accuracy_and_precision
Data values taken at 4 points might be 42, 39, 41, 36. The spread (or precision per the "standard" below) of these values is 6.
The only measuring device we have currently has a repeatability and accuracy of +/ 1.5 microns. For determining how much error this device takes up from the thickness specification I think its just 12/3 which is 25% of that +/6 tolerance. For the precision range would that be calculated the same resulting in 50%?
I am posting an ISO standard since I am trying to use standard definitions which seem to vary quite a bit  "trueness" instead of "accuracy" for example.
https://en.wikipedia.org/wiki/Accuracy_and_precision
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