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st: RE: Different sign in two model

From   "Martin Weiss" <>
To   <>
Subject   st: RE: Different sign in two model
Date   Sun, 12 Jul 2009 17:30:54 +0200


Attachments are explicitly prohibited on Statalist. A glance at yours shows
that you could easily transmit the same information using the -input-
command in the body of your email...


-----Original Message-----
[] On Behalf Of Song Nhac
Sent: Sonntag, 12. Juli 2009 17:17
Subject: st: Different sign in two model

Dear All,

I am a newcomer of Stata. I searched for a while in archives list but there
is no related topic to this, so I have a question about my
I employed Weibull model and Log logic model to test my data, but, I
received two different sign in alpha and beta In Weibull: beta= -.3503182
and alpha=2.669465 (negative in beta) but in Log logic: beta= .8955857 and
alpha= -.4768999 (negative in
alpha)- I expect beta is negative in this model but it did not.
 I use the same data set, in which the dependent variable is
(survival) as in attached data set. and independent variable is
I followed the guideline in "maximum likelihood estimation with stata- 3rd
edition" to do those tests. So what could I explain for those results?

Thank for your kindly support,
Best regards,
Ha Pham

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