Optimizing Intermodal Transport and Hub Location Problem for ECOWAS in the Context of Improving Intra-African Trade

Table 3

Summary coefficients on gravity model estimates.

Variables	Coef.	Std. Err.	Sig
LN (GDPGDP)	0.9810841	0.0065849
LN (PopPop)	0.0069167	0.0059408
LN (ABS (GDP-GDP)	−0.0050114	0.0065017
LN (Distance)	−0.1599074	0.0590544
LN (CPI + CPI)	−0.2225097	0.0903401
LN (PI + PI)	0.0005157	0.0166238
Common language	0.0001123	0.0013987
No. of obs		3,900
Adj R-Squared		0.9247

Note., , and show the level of significance at 10%, 5%, and 1%, respectively.