看stata的help 的 xtreg postestimation的解释啊。
这些东西你是不能猜想的。
为什么自己找一下help就这么困难呢?
里面讲的都很清楚的
help xtreg postestimation predict dialogs: re/be/fe/mle pa
dialog: xttest0
also see: xtreg
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Title
[XT] xtreg postestimation -- Postestimation tools for xtreg
Description
The following postestimation commands are of special interest after xtreg:
command description
-----------------------------------------------------------------------------------------------
xttest0 Breusch and Pagan LM test for random effects
-----------------------------------------------------------------------------------------------
The following standard postestimation commands are also available:
command description
-----------------------------------------------------------------------------------------------
(1) estat AIC, BIC, VCE, and estimation sample summary
estimates cataloging estimation results
hausman Hausman's specification test
lincom point estimates, standard errors, testing, and inference for linear
combinations of coefficients
lrtest likelihood-ratio test
margins marginal means, predictive margins, marginal effects, and average marginal
effects
nlcom point estimates, standard errors, testing, and inference for nonlinear
combinations of coefficients
predict predictions, residuals, influence statistics, and other diagnostic measures
predictnl point estimates, standard errors, testing, and inference for generalized
predictions
test Wald tests of simple and composite linear hypotheses
testnl Wald tests of nonlinear hypotheses
-----------------------------------------------------------------------------------------------
(1) estat ic is not appropriate with xtreg, be, xtreg, pa, or xtreg, re.
Special-interest postestimation commands
xttest0, for use after xtreg, re, presents the Breusch and Pagan Lagrange multiplier test for
random effects, a test that Var(v_i)=0.
Syntax for predict
For all but the population-averaged model
predict [type] newvar [if] [in] [, statistic nooffset]
Population-averaged model
predict [type] newvar [if] [in] [, PA_statistic nooffset]
statistic description
-----------------------------------------------------------------------------------------------
Main
xb xb, fitted values; the default
stdp calculate standard error of the fitted values
ue u_i + e_it, the combined residual
* xbu xb + u_i, prediction including effect
* u u_i, the fixed- or random-error component
* e e_it, the overall error component
-----------------------------------------------------------------------------------------------
Unstarred statistics are available both in and out of sample; type predict ... if e(sample) ...
if wanted only for the estimation sample. Starred statistics are calculated only for the
estimation sample, even when if e(sample) is not specified.
PA_statistic description
-----------------------------------------------------------------------------------------------
Main
mu probability of depvar; considers the offset()
rate probability of depvar
xb calculate linear prediction
stdp calculate standard error of the linear prediction
score first derivative of the log likelihood with respect to xb
-----------------------------------------------------------------------------------------------
These statistics are available both in and out of sample; type predict ... if e(sample) ... if
wanted only for the estimation sample.
Menu
Statistics > Postestimation > Predictions, residuals, etc.
Options for predict
+------+
----+ Main +-----------------------------------------------------------------------------------
xb calculates the linear prediction, that is, a + bx_it. This is the default for all except
the population-averaged model.
stdp calculates the standard error of the linear prediction. For the fixed-effects model, this
excludes the variance due to uncertainty about the estimate of u_i.
mu and rate both calculate the predicted probability of depvar. mu takes into account the
offset(), and rate ignores those adjustments. mu and rate are equivalent if you did not
specify offset(). mu is the default for the population-averaged model.
ue calculates the prediction of u_it + e_it.
xbu calculates the prediction of a + bx_it + u_i, the prediction including the fixed or random
component.
u calculates the prediction of u_i, the estimated fixed or random effect.
e calculates the prediction of e_it.
score calculates the equation-level score.
nooffset is relevant only if you specified offset(varname) for xtreg. It modifies the
calculations made by predict so that they ignore the offset variable; the linear prediction
is treated as xb rather than xb + offset.
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