Table 3.

The credibility analysis of the regression equations

Index mark	Average forward extraction efficiency
	α′	α	β
SD	2.07	4.01	2.21
Mean	58.95	48.22	45.91
C.V.(%)	3.52	8.33	4.82
Adequacy precision	25.66	9.34	21.15
Press	292.56	1807.57	105.34
R-squared	0.9906	0.9344	0.9867
Adjust R-squared	0.9784	0.8502	0.9695
Predicted R-squared	0.9082	− 0.0489	0.9591

CV coefficient of variation