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RE: AW: st: sort of standardization


From   "Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   RE: AW: st: sort of standardization
Date   Wed, 12 May 2010 13:24:03 -0700

I think Rich is thinking of the number of distinct integers between 1 and 10, while the range is generally defined as the largest minus the smallest.

Tony

Peter A. Lachenbruch
Department of Public Health
Oregon State University
Corvallis, OR 97330
Phone: 541-737-3832
FAX: 541-737-4001


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox
Sent: Wednesday, May 12, 2010 11:16 AM
To: statalist@hsphsun2.harvard.edu
Subject: RE: AW: st: sort of standardization

The word "range" is surely ambiguous, although the ambiguity does not
bite hard. I have no difficulty in saying both that the range is the
interval [1,10] and that the range is the difference 9. Does that differ
from Rich's view? 

Nick 
n.j.cox@durham.ac.uk 

Richard Goldstein

look at it this way -- if my min is 1 and my max is 10, then the range
is 10 (it seems to me), not 9 -- i.e., I think of the range as the min
to the max *inclusive* of each endpoint; StataCorp apparently disagrees
;-)

On 5/12/10 10:46 AM, Martin Weiss wrote:

> " local range=r(max)-r(min)+1"
> 
> Rich, what does the "+1" term do for the "range"? I took the
definition in
> my code from [R], page 204. Am I missing anything?

Richard Goldstein
 
> if I understand correctly what you want, I would do the following
within
> a -foreach- loop:
> 
> summarize variable
> calculate the range from r(min) and r(max)
> divide the old variable by this calculated range inside a -gen-
> 
> e.g.,
> 
> foreach var of varlist .... {
> qui su `var'
> local range=r(max)-r(min)+1
> gen `var'3=`var'/`range'
> }

> On 5/12/10 10:29 AM, Ginevra Biino wrote:

>> I have to standardize many variables (in order to run PCA).
>> Besides generating the n corresponding std(varname) vars, which I
have
>> already done, I also want to generate n new  variables obtained
dividing
>> each variable by its range. Can anybody help me?

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