Table 5.

The statistical results of the external test set for the three models of each group.

	Group 1		Group 2		Group 3
	MLR	RBFNN	MLR	RBFNN	MLR	RBFNN
R 2	0.83	0.84	0.80	0.82	0.85	0.89
${\mathrm{q}}_{\mathrm{ext}}^2$	0.92	0.88	0.79	0.81	0.73	0.63
$R_0^2$	0.81	0.84	0.79	0.82	0.84	0.88
$\frac{\left(R^2-R_0^2\right)}{R^2}$	0.024	0.00	0.012	0.00	0.012	0.011
k	0.88	0.86	0.80	0.83	0.85	0.87
k′	1.11	0.97	0.93	0.91	0.93	0.98