Table 9: Granger causality relationship test.

Null Hypothesis:	Obs	F-Statistic	Prob.
R_BJCOAL does not Granger Cause R_RGI	47	0.523	0.719
R_RGI does not Granger Cause R_BJCOAL		2.714	0.045**
R_QHDCOAL does not Granger Cause R_RGI	48	2.455	0.077*
R_RGI does not Granger Cause R_QHDCOAL		1.192	0.326