Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

st: q-q plots, theoretical distribution with values higher than the sample's cutoff point


From   Lucia Latino <Latino@economia.uniroma2.it>
To   statalist@hsphsun2.harvard.edu
Subject   st: q-q plots, theoretical distribution with values higher than the sample's cutoff point
Date   Wed, 18 Jul 2012 18:13:50 +0200

Dear Statalist,

I am having some problems with the q-q plots for Dagum, gb2, lognormal and Singh-Maddala distributions using programs written by Nick Cox.

After having fit the distribution (e.g. lognfit dec_ae, svy), I run the command for the q-q plot (e.g. qlogn dec_ae [pweight=iwght]).

I repeat the same procedure for the other distributions (Dagum, gb2 and Singh-Maddala). All the plots show a strange behavior: in all the qq-plots, the points follow a strongly nonlinear patters. At the beginning they follow the 45 degree line, then they depart significantly from the 45 degree line and become flat around the value 10,000, which is the max value for dec_ae.

What does it mean? Why the theoretical distribution takes value higher than 10,000?

I hope I was clear enough. I wish I could show you the plots, but I understood I cannot attach them.

Best,
Lucia


----------------------------------------------------------------
Invito da parte dell'Ateneo:
Il tuo futuro e quello della Ricerca Scientifica hanno bisogno del
tuo aiuto. Dona il  5 x mille all'Universita' di Roma Tor Vergata
codice fiscale: 80213750583 http://5x1000.uniroma2.it


*
*   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/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index