模型1

模型2

模型3

模型4

prot

disc

prot

prot

prof

0.059^***

(3.022)

0.065^***

(2.844)

0.055^***

(2.814)

disc

0.067^***

(3.401)

0.063^***

(3.217)

jr

−0.109^***

(−5.465)

−0.037

(−1.593)

−0.105^***

(−5.265)

−0.106^***

(−5.357)

lnpay

0.100^***

(4.566)

0.096^***

(3.771)

0.095^***

(4.340)

0.094^***

(4.283)

share

0.052^**

(2.562)

0.026

(1.085)

0.045^**

(2.235)

0.050^**

(2.488)

lev

−0.260^***

(−11.569)

−0.097^***

(−3.714)

−0.251^***

(−11.143)

−0.254^***

(−11.282)

fir

−0.402^***

(−20.080)

0.036

(1.526)

−0.406^***

(−20.250)

−0.405^***

(−20.230)

aud

0.037^*

(1.883)

0.005

(0.203)

0.035^*

(1.765)

0.037^*

(1.873)

sta

−0.006

(−0.303)

0.021

(0.934)

−0.009

(−0.468)

−0.007

(−0.373)

lnsize

−0.057^**

(−2.356)

−0.012

(−0.430)

−0.058^**

(−2.359)

−0.057^**

(−2.330)

Adj-R²

0.279

0.021

0.280

0.282

F值

82.999^***

5.569^***

83.373^***

76.101^***