“…The predictive correlation coefficient values ( R 2 pred ), r 2 , k , k’ , r 0 2 , r 0 ’ 2 , r m 2 , r m ’2 , Δ r m 2 ,
are the essential parameter to prove how capable the model is of making positive external predictions. And the ideal model needs to meet R 2 pre d greater than 6, both the value of r m 2 and r m ’2 are higher than 0.5, k and k’ are in the range of 0.85 and 1.15, Δ r m 2 is lower 0.2,
larger than 0.5
[27–29] . Furthermore, the most significant external prediction parameters R 2 pred of the model is calculated as follows:
[20,30] …”