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

st: Decision on trimming the data


From   Rijo John <[email protected]>
To   Statalist <[email protected]>
Subject   st: Decision on trimming the data
Date   Tue, 22 Jun 2004 18:33:04 +0530 (IST)

Dear Stata users,

 I have a data set with quite a few outliers. Suppose I am trimming my
dependent  variable 1% each from top and bottom using 1st and 99th
percentiles. And I have the regression estimates before and after
trimming. Let us also suppose that some of the variables that were
significant before trimming turned out to be insignificant after trimming
and/or viceversa.

 Is there a standard way by which one can decide how much percentage
of data should be trimmed? Is a chow test for the equality of coefficients
enough for this? I mean trim upto the point where the changes in
coefficients becomes insignificant? Or is there any other standard way to
do this?

Thanks in advance...

Rijo John.

***************************************************
Rijo.M.John,Research Scholar
Indira Gandhi Institute of Developement Research,
Film City Road, Goregaon East,
Mumbai, India-400065.
contact: (+91)9892412476



*
*   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