Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: RE: Constraining Weibull Parameter p


From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   st: RE: Constraining Weibull Parameter p
Date   Thu, 5 Dec 2002 19:48:31 -0000

Marita Jacob
> 
> How do I impose the restriction that the shape parameter p 
> of the weibull 
> distribution is less than 1 (i.e. monotonic decreasing 
> hazardfunction) ?
> 
> constraint define 1 [equation_name]coeff_name ??? < 1
> weibull t, dead(dead) hazard constraint(1)
> 

As I understand it, -constraint- only accepts constraints 
definable as equalities. 

Perhaps there is some algebraic 
re-expression of the model which 
would satisfy this inequality indirectly. 

On the other hand: If this 
assumption is realistic, you should 
not need a constraint. If this 
assumption is not realistic, what 
justifies this desire for force? 

Nick 
[email protected] 

*
*   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/



© Copyright 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index