S = \hat \mu_3(\delta x) = \hat \mu_3(x-\hat x)

where 

observed  variable represented by a discrete  dataset of numerical samples

predictor of variable , represented by another discrete  dataset of numerical samples,

with the same number of samples  predicted at the same conditions as the original samples 

discrepancy dataset

3-rd order standardized central momentum of the discrepancy dataset 


See also


Natural Science / System / Model / Model Validation

Formal science / Mathematics / Statistics Statistical correlation / Correlation coefficient