Hi, Listers
I have a panel dataset. My problem is the xtreg and reg give out the
same result, can you tell me why?
. xtreg invest l_tobinq so1_q so2_q cash so1_cf so2_cf nta
Random-effects GLS regression Number of obs = 1680
Group variable (i) : i Number of groups = 280
R-sq: within = 0.1172 Obs per group: min = 6
between = 0.5438 avg = 6.0
overall = 0.1890 max = 6
Random effects u_i ~ Gaussian Wald chi2(7) = 389.67
corr(u_i, X) = 0 (assumed) Prob > chi2 = 0.0000
invest Coef. Std. Err. z P>z [95% Conf. Interval]
l_tobinq .1158289 .0633886 1.83 0.068 -.0084104 .2400682
so1_q -.0308517 .0497988 -0.62 0.536 -.1284555 .0667521
so2_q -.0413252 .0666455 -0.62 0.535 -.171948 .0892976
cash .1281167 .008567 14.95 0.000 .1113257 .1449078
so1_cf .2623394 .0345842 7.59 0.000 .1945556 .3301232
so2_cf .15333 .1796647 0.85 0.393 -.1988064 .5054664
nta -.1325352 .070429 -1.88 0.060 -.2705735 .0055031
_cons 3.003068 1.49794 2.00 0.045 .0671603 5.938975
sigma_u 0
sigma_e 2.5762731
rho 0 (fraction of variance due to u_i)
. reg invest l_tobinq so1_q so2_q cash so1_cf so2_cf nta
Source SS df MS Number of obs = 1680
F( 7, 1672) = 55.67
Model 2449.83361 7 349.97623 Prob > F = 0.0000
Residual 10511.6469 1672 6.28687016 R-squared = 0.1890
Adj R-squared = 0.1856
Total 12961.4805 1679 7.71976207 Root MSE = 2.5074
invest Coef. Std. Err. t P>t [95% Conf. Interval]
l_tobinq .1158289 .0633886 1.83 0.068 -.0085004 .2401582
so1_q -.0308517 .0497988 -0.62 0.536 -.1285262 .0668228
so2_q -.0413252 .0666455 -0.62 0.535 -.1720426 .0893922
cash .1281167 .008567 14.95 0.000 .1113135 .14492
so1_cf .2623394 .0345842 7.59 0.000 .1945065 .3301723
so2_cf .15333 .1796647 0.85 0.394 -.1990615 .5057214
nta -.1325352 .070429 -1.88 0.060 -.2706735 .0056031
_cons 3.003068 1.49794 2.00 0.045 .0650335 5.941102
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