论文模型 coreroa=α+α1 cos+α2 Size+α3 D/A+α4 Id+α5 Bsize +α6 State+ε
怀疑cos存在内生性,选择 beta divid liq3个为它的工具变量
下面是IV2SLS回归结果
Instrumental variables (2SLS) regression Number of obs = 1305
Wald chi2(6) = 67.76
Prob > chi2 = 0.0000
R-squared = .
Root MSE = .19033
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coreroa | Coef. Std. Err. z P>|z| [95% Conf. Interval]
-------------+----------------------------------------------------------------
cos | .2157364 .0345957 6.24 0.000 .1479301 .2835426
size | .0378036 .0090836 4.16 0.000 .0200001 .055607
debt | -.2614605 .0393988 -6.64 0.000 -.3386806 -.1842404
id | .0601476 .0659236 0.91 0.362 -.0690603 .1893555
bsize | -.0004875 .0015174 -0.32 0.748 -.0034615 .0024864
state | .1083073 .0342084 3.17 0.002 .04126 .1753545
_cons | -.9585905 .2218373 -4.32 0.000 -1.393384 -.5237974
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Instrumented: cos
Instruments: size debt id bsize state beta divid liq
问题:请问“R-squared= . ” 说明什么问题?可以通过 对 模型 加变量 解决吗?谢谢!


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