Thanks to Kit Baum a update of the -betafit- package is now available on
SSC. This package is written Nick Cox, Stephen Jenkins and me, and fits a
beta distribution to your data. This is a flexible distribution for
variables that are boundend between zero and one. An important application
are regression-like analyses when the depedent variable is a proportion.
This update improved the likelihood function such that it is more
numerically stable. In simulations the old likelihood function had trouble
in case of strong bi-modality of the dependent variable when using the
alternative parameterization. This update fixes that problem. (For those
who are interested in the technical details: I replaced occurences of
1-invlogit(xb) by invlogit(-xb) )
To update this package when it is already installed on your machine type
in Stata -ssc install betafit- or -adoupdate, update-. To install
-betafit- type in Stata: -scc install betafit-.
-- Maarten
--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://www.maartenbuis.nl
--------------------------
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