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st: update hangroot


From   Maarten buis <maartenbuis@yahoo.co.uk>
To   statalist@hsphsun2.harvard.edu
Subject   st: update hangroot
Date   Mon, 12 Nov 2007 16:58:30 +0000 (GMT)

Thanks to the ever patient Kit Baum the -hangroot- package has now been
updated. -hangroot- creates a hanging rootogram, which is a graph
comparing an empirical distribution with a theoretical one. In the
previous version the only theoretical distirbution implemented was the
normal distribution. I have now added the beta distribution, the pareto
distribution, and the poisson distribution. Depending on my need for
procrastination I will add more distributions in later updates.

A hanging rootogram is an alternative for a histogram with the density
funciton of the theoretical distribution plotted through it. It differs
from a histogram in two ways:

1) Instead of showing the freqencies it shows the square root of the
frequencies.  This way deviations in the tails, where the counts are
small, become more visible.

2) The spikes or bars "hang" from the theoretical distribution instead
of "standing" on the x-axis. The deviations are now shown as deviations
from a horzontal line (y=0) instead of deviations from a curve (the
density function). This makes it easier to spot patterns in the
deviations.

-- 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/
-----------------------------------------


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