BUCHI NIRCal - Manual (Page 163)

Chemometrics
NIRCal 5.5 Manual, Version A 163
Important:
The statistics only gives relevant estimates of calibration performance if the prediction protocol is
made using an independent test set.
The statistics reported here can deviate from what is reported in the Original vs Predicted Property
plots of two reasons: 1) outliers are not included, and 2) the linear regression to find slope and offset
is made using the predicted values as the independent variable.
Definitions
The prediction protocol includes the following statistics:

Offset

Slope

RMSEP

SEP

RSD

Bias
The following figure explains some of the statistics.
The vector of difference between the predicted and the reference values for sample i is defined as
:
Where y
i
is the reference value for sample i, ŷ
i
is the predicted value for sample i and e
i
is the residual
for sample i.
Bias: The bias is calculated as the mean of the differences.