Regions

S1

S2

S3

F2

F3

Conclusions

China

0.24432

2.67645

11.63396

2.062182

8.047626

Variable coefficient model

The east

0.11198

0.74967

3.68426

1.264505

5.901351

Variable intercept model

The central

0.02545

0.27442

0.22994

2.276571

1.554286

Constant coefficient model

The west

0.10823

0.8668

2.54523

1.531852

4.128395

Variable intercept model