How to report a measurement and relate it to calibration certificate

surfing69

Registered
we recently purchased an anemometer which was calibrated at 3 points i.e. 0.5m/s. 1.0m/s and 2.0 m/s.

We want to carry out periodic measurements of our fume cupboard to make sure its still operating properly. The calibration data for the anemometer is shown below

View media item 4603
when we measured our fume cupboard at 9 points across the face we obtained an average face velocity of 0.38 +/- 0.08 m/s. If I generate a graph of True reading vs Instrument measure value, I can calculate the true reading that corresponds to the measured value of 0.38 m/s.

However how do i report the uncertainty for this measure value?

1. do i just report the SD of +/- 0.08 ?
2. somehow combine the SD ( no idea how to do this) of the measured average value with the uncertainty of measurement from the calibration certificate?
3. not report any uncertainty for the measured average value?

Any guidance would be greatly appreciated.

Thanks
 

dwperron

Trusted Information Resource
However how do i report the uncertainty for this measure value?

1. do i just report the SD of +/- 0.08 ?
2. somehow combine the SD ( no idea how to do this) of the measured average value with the uncertainty of measurement from the calibration certificate?
3. not report any uncertainty for the measured average value?


You would need to include normalized uncertainty contributors such as accuracy of your meter, repeatability of the meter, resolution of the meter, stability of the meter, any environmental effects on the meter, etc. and then combine them through RSS.

As for the bigger question, why do you need the measurement uncertainty? If it is required then take the readings and do the math. If there is no requirement to report the measurement uncertainty then I would avoid the effort.
 
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