Table 6.

Robustness test.

Variable	Coefficient estimate	T-value
lnagg*I(q≦γ1)	−1.9245***	−7.8636
nagg*I(γ1 < q≦γ2)	−2.6178***	−8.0933
nagg*I(q>γ2)	−1.9835***	−6.1848
lntec	−0.7678***	−11.3619
lnstr	−1.4611***	−7.9383
lnreg	0.1364***	6.9162

^***, and ^*are significant at the level of 1, and 10% respectively.