Table 2.

Unit root test (Ng and Perron)

Variable (s)		MZα	MZt	MSB	MPT	Order
CO2e	At level	− 0.33252	− 0.24787	0.74543	31.4831
	At first-diff	− 12.5924	− 2.50871	0.19922	1.94757	I(1)
TOR	At level	− 0.24526	− 0.14437	0.58865	22.5741
	At first-diff	− 12.4824	− 2.49484	0.19987	1.97574
Y	At level	− 1.43573	− 0.60496	0.42136	12.0085	I(1)
	At first-diff	− 11.854	− 1.90708	0.16088	3.87271
FDI	At level	− 14.6622	− 2.70727	0.18464	1.67218	I(0)
	At first-diff	− 11.3358	− 2.3807	0.21002	2.16145
RE	At level	− 0.18096	− 0.13688	0.75639	33.3865	I(1)
	At first-diff	− 12.7632	− 2.52435	0.19778	1.9266
	Critical-values at 1%	− 13.8	− 2.58	0.174	1.78
	Critical-values at 5%	− 8.1	− 1.98	0.233	3.17
	Critical-values at 10%	− 5.7	− 1.62	0.275	4.45