Dear Maarten
Thank you for your reply. Yes, it is a reference category. After sending
the e-mail, I realised that standard error is missing from the same
variable when I run probit instead of dprobit. I think the main problem
is that the model contains too many dummy variables as when I drop some
of them, all the standard errors are estimated. I am wondering, however,
if there are any solutions other than dropping variables.
Best Wishes,
Asako
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Maarten buis
Sent: 26 November 2007 22:23
To: [email protected]
Subject: Re: st: missing z-values when using dprobit
--- "Ohinata, Asako" <[email protected]> wrote:
> Dear All
>
> I am currently running dprobit with many dummy variables as well as
> some continuous variables (i.e. age etc). When I run the regression,
> some of the z-values are missing although standard errors are
> estimated.
>
> Y | dF/dx Std. Err. z
> kid3plus*| 1 2.86e-71 . <snip>
> Could you please let me know when STATA compute standard errors but
> not z-values?
The standard error is in the example is very very small (0.0000000000000
00000000000000000000000000000000000000000000000000000000286), i.e. de
facto zero. So I am not surprized the z-score is missing. Is kid3plus
the reference category?
-- 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/
-----------------------------------------
___________________________________________________________
Want ideas for reducing your carbon footprint? Visit Yahoo! For Good
http://uk.promotions.yahoo.com/forgood/environment.html
*
* 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/
*
* 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/
