蓝色 发表于 2007-4-5 08:20
计量经济学的书啊,或者查他们的文章
老师,您好,我在检测lnsr是否存在内生性的过程中,进行了如下回归:
reg lnxf lnsr you old pop lninf
estimates store ols
ivregress 2sls lnxf you old pop lninf ( lnsr= lnf )
estimates store iv
. hausman iv ols, constant sigmamore
Note: the rank of the differenced variance matrix (3) does not equal the number of coefficients being
tested (4); be sure this is what you expect, or there may be problems computing the test.
Examine the output of your estimators for anything unexpected and possibly consider scaling your
variables so that the coefficients are on a similar scale.
---- Coefficients ----
| (b) (B) (b-B) sqrt(diag(V_b-V_B))
| iv ols Difference S.E.
-------------+----------------------------------------------------------------
lnsr | 3.548807 .3330421 3.215765 5.27595
old | .008242 .0057248 .0025171 .
lninf | .0068528 .0576194 -.0507665 .0832902
_cons | -.2250452 .055597 -.2806422 .460436
------------------------------------------------------------------------------
b = consistent under Ho and Ha; obtained from ivregress
B = inconsistent under Ha, efficient under Ho; obtained from regress
Test: Ho: difference in coefficients not systematic
chi2(3) = (b-B)'[(V_b-V_B)^(-1)](b-B)
= 0.37
Prob>chi2 = 0.9461
(V_b-V_B is not positive definite)
estat endogenous
Tests of endogeneity
Ho: variables are exogenous
Durbin (score) chi2(1) = .379412 (p = 0.5379)
Wu-Hausman F(1,234) = .370512 (p = 0.5433)
最后的命令用了Durbin-Wu-Hausman 内生性检验,其他论文只给出了
Durbin-Wu-Hausman 内生性检验 8.281[0.004],
但是我的结果显示了Durbin (score) chi2(1)和 Wu-Hausman F(1,234)两个值???