st: new version zoib available from SSC

[Maarten Buis <maartenlbuis@gmail.com>]

Thanks to Kit Baum a new version of the -zoib- package is now
available from SSC.

-zoib- fits by maximum likelihood a zero-one inflated beta
distribution to a distribution of a variable depvar. depvar ranges
between 0 and 1: for example, it may be a proportion.     It will
estimate the proportions between 0 and 1 as a beta distribution and
the probabilities of having the value 0 and/or 1 as separate
processes. The logic is that we can often think of proportions of 0 or
1 as being qualitatively different and generated through a different
process as the other proportions. More can be found here:
<http://www.maartenbuis.nl/software/zoib.html>

In this update I fixed a bug in the predict function of -zoib- when
both 0s and 1s are present in depvar. Embarrassingly, I switched the
zero and the one inflation equations. I thank Jeroan Allison for
pointing this out to me.

I hope some of you will find this useful,
Maarten

-- 
---------------------------------
Maarten L. Buis
WZB
Reichpietschufer 50
10785 Berlin
Germany

http://www.maartenbuis.nl
---------------------------------
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/