|
|  |
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]
RE: st: RE: Standard error
Hi Maarteen,
thanks for ur help. i understand what you mean, but if i was asked to
compare the Standard error of the variable wage (one of the independent
variable) for two regression (one OLS and one under heckit), and found out
the SE for wage is bigger in heckit, than OLS, what does that imply?
also for rho, i had an estimate for 0.38, but no chi result. what does the
0.38 reflect?
thank you ever so much in advance.
regard
jo
From: "Maarten Buis" <[email protected]>
Reply-To: [email protected]
To: <[email protected]>
Subject: RE: st: RE: Standard error
Date: Fri, 20 Apr 2007 14:06:22 +0200
--- Joanne Marshall wrote:
> I would like to ask when i have applied heckit model to the regression,
if i
> found the standard error of the particular variable (say wage in this
case)
> has gone up than the standard error predicted by the OLS model, (from
0.13
> to 0.26) does this suggest there is evidence of sample selection problem
in
> estimating the equation and if there is a more in depth meaning?
The standard errors in your equation of interest won't tell you whether or
not there is selection. However, -heckman- will give you a test. The bottom
line of the output will read something like:
LR test of indep. eqns. (rho = 0): chi2(1) = 0.26 Prob > chi2 =
0.6109
If that Prob > chi2 is less than .05 you can reject the hypothesis that
there
is no selection.
Hope this helps,
Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
_________________________________________________________________
Could you be the guest MSN Movies presenter? Click Here to Audition
http://www.lightscameraaudition.co.uk
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
