BUCHI DuMaster D-480 - Manual (Page 182)

Operation Manual D-480 ©BÜCH Labortechnik AG
8 - Maintaining the instrument 182
Assessing the calibration curves
Calibration curve display in the calibration view
After the calibration curves have been computed, the calibration points and the calibration curve for
the respective element are displayed in the calibration view. The individual calibration points are
displayed as circles. The following picture shows an example of a calibration curve for the nitrogen
element.
Displayed characteristics
The following table explains the characteristics relating to the calibration curve, as displayed in the
above picture:
Characteristic Description
Zoom Shows the current graph zoom factor.
a...e Coefficients of the current polynomial.
r Quality factor for the degree of fit of the current curve calculation.
 For a polynomial calculation of the first degree, "r" is the correlation
coefficient. The optimum is 1.
 For polynomial calculations of a higher degree, "r" is the sum of error
squares. The optimum is 0.
r_old Quality factor for the degree of fit of the last curve calculation. It is used for
comparison with "r". This allows you, for example, to check whether it makes
sense to delete certain samples.
Proc-SD Process standard deviation: a measure of the degree of distribution of sample
values around the calibration curve.