如果不等价,该如何test是否该采用变截距模型?
如等价,如何从stata中的xtrc命令得到验证?据经验判断,
andom-coefficients regression Number of obs = 480
Group variable: code Number of groups = 30
Obs per group: min = 16
avg = 16.0
max = 16
Wald chi2(1) = 1.15
Prob > chi2 = 0.2826
------------------------------------------------------------------------------
lagre | Coef. Std. Err. z P>|z| [95% Conf. Interval]
-------------+----------------------------------------------------------------
lagri | -.0902102 .0839584 -1.07 0.283 -.2547657 .0743453
_cons | 7.054528 .4540896 15.54 0.000 6.164528 7.944527
------------------------------------------------------------------------------
Test of parameter constancy: chi2(58) = 1.6e+05 Prob > chi2 = 0.0000
一般会拒绝等参数的原假设,如上表。