模型

1

2

3

4

5

gdp

0.0013^***

0.0016^***

0.0015^***

0.0016^***

(−3.28)

(−5.98)

(−5.29)

(−6.02)

tertiary

0.0447^***

0.00303

0.044^***

(−4.81)

(−0.43)

(−4.55)

covid_19

−0.520^***

−0.529^***

−0.515^***

(−11.7)

(−13.8)

(−12.0)

highway

0.00028

0.0086^***

0.0068

(−0.94)

(−2.73)

(−1.55)

_cons

−4.342^***

0.283

0.643^***

0.775^***

−4.149^***

(−4.39)

(−0.37)

(−14.1)

(−18.1)

(−4.00)

sigma

0.292^***

0.192^***

0.191^***

0.215^***

0.303^***

−14.49

−14.49

−14.49

−14.49

−14.49

Log lik.

−19.77

24.27

24.61

12.2

−23.71

Chi2

30.21

118.3

119

94.14

22.33

N

105

105

105

105

105