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

st: handling of discrete variables

From   Thomas M�hlmann <[email protected]>
To   [email protected]
Subject   st: handling of discrete variables
Date   Mon, 20 Oct 2003 15:41:18 +0200

Dear Statalist,

I have a statistical question concerning the handling of discrete
variables.  I apologize if the question sounds a bit simple or is not a
direct stata question.

Suppose we have two discrete variables (y and x) with each three
categories (coded 0, 1 and 2). This results in a 3x3 contingency tabel
with m=9 different cells. Now, it seems to me, that I have two
possibilities to incorporate x and y in regression like analysis:

1) Use four dummy variables, two for x and two for y (additional we can
use interaction terms)
2) Use one dummy for each of the m-1=8 cells of the contingency tabel.

My questions are:
What are the differences between these two possibilities, what are the
effects of using more dummies in 2)?
How can I reconcile 1) and 2) ?

I would deeply appreciate any comments or references concerning the
topic above!

org:Universit�t zu K�ln;Bankseminar
adr:;;Albertus-Magnus-Platz;50923 K�ln;;;
email;internet:[email protected]
fn:Dipl.-Kfm. Thomas M�hlmann

© Copyright 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index