Statalist


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

RE: st: Create a normalized variable


From   Maarten buis <maartenbuis@yahoo.co.uk>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: Create a normalized variable
Date   Thu, 20 Nov 2008 18:19:41 +0000 (GMT)

--- Nick Cox <n.j.cox@durham.ac.uk> wrote:
> Roughly speaking, my experience is that natural scientists
> (physicists, biologists, etc.) are more likely to take normalised as
> meaning scaled to [0, 1], far more commonly by 
> (value - min) / (max - min) than by percentile ranks. The more
> statistics you know, the more likely you are to regard 
> (value - mean) / sd as a natural standardisation. 

The funny thing is that (value - mean) / sd scores are often
interpreted in terms of percentile ranks: a value of -2 can usually be
considered small because, if the variable is reasonable close to a
Gaussian distribution, one would expect that approximately 2.5% of the
respondent would have a smaller value (and thus 97.5% of the
respondents to have a larger value). That looks suspiciously like a
percentile rank to me... This is one of the reasons why I think that
there is quite some merit in using percentile ranks as a form of
standardization.

-- 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 N515

+31 20 5986715

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


      
*
*   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   |   What's new   |   Site index