[Retracted] Foreign Direct Investment, Regional Innovation, and Green Economic Efficiency: An Empirical Test Based on the Investigation of Intermediary Effect and Threshold Effect

Table 8

Robustness test results.

Variables	GMM	Variables	GMM
LnGECMit−1	0.4157	AR(2)	−0.5900
	[2.07]		(0.554)
FDIit^2LnFDIit	−5.67e−08	Hansen	21.1100
	[−1.71]		(0.133)
FDIitLnFDIit	0.0001	F	9.5300
	[1.91]		(≤0.001)
Control variable	Control	—	—