Table 2. The relation of error/accuracy measures and data properties.

Error/accuracy Measure	Unit/scale independent	Variance-independent	Predictive accuracy	Relationship with VEcv*
MAE	No	No	Unknown	$\sqrt{\raisebox{1ex}{$(1-VEcv/100)(n-1)$}\!\left/ \!\raisebox{-1ex}{$2.0572n$}\right.}s$
RMSE	No	No	Unknown	$\sqrt{(1-VEcv/100)(n-1)/n}s$
MSE	No	No	Unknown	$((1-VEcv/100)(n-1)/n)s^2$
RMAE	Yes	No	Unknown	$\sqrt{\raisebox{1ex}{$(1-VEcv/100)(n-1)$}\!\left/ \!\raisebox{-1ex}{$2.0572n$}\right.}CV$
RRMSE	Yes	No	Unknown	$\sqrt{(1-VEcv/100)(n-1)/n}CV$
SRMSE	Yes	Yes	Unknown	$\sqrt{(1-VEcv/100)(n-1)/n}$
MSRE	Yes	Yes	Unknown	$(1-VEcv/100)(n-1)/n$
VEcv	Yes	Yes	Known

* These equations were derived from Li [18], where n is the number of observations in, s is standard deviation of, and CV is coefficient of variation of, a validation dataset