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Calibration Uncertainty

Posted: Sat Apr 01, 2017 5:58 pm
by ucanmoruk
Hi,

On a validation study, calculating uncertainty from linearity a formule is using like that according to Eurachem's Quantifying Uncertainty Guide (page 77);

Image

I don't understand that; on the (Co-C)^2 side of the formula, could I use the average value of the calibration points or any point in the calibration range or a sample that entering calibration range?

When I calculate the uncertainty of the calibration its so bigger than the other uncertainty and so that I do not include it in total uncertainty. Is it true?

Re: Calibration Uncertainty

Posted: Sat Apr 01, 2017 7:30 pm
by Peter Apps
??

That equation is for calculating the uncertainty of the measurement result, not the uncertainty of the calibration. For the uncertainty of the calibration see p 115.

Peter

Re: Calibration Uncertainty

Posted: Sat Apr 01, 2017 7:52 pm
by ucanmoruk
Peter Apps wrote:
??

That equation is for calculating the uncertainty of the measurement result, not the uncertainty of the calibration. For the uncertainty of the calibration see p 115.

Peter


But the formulas are similar. There again only one x value is used and I wondered that the X value the top point of the calibration points or the mean of the calibration points.

Re: Calibration Uncertainty

Posted: Sat Apr 01, 2017 8:16 pm
by Peter Apps
Equations 3.4, and 3.5 on p 115 both include x subscript i - that means you use the individual values of response against quantity.

Peter