Yes, it will scale the sd up to 1 and you can expect most data to fall between -3 and 3.  
   
  The more important question is why are you transforming.  A z-transformation is done to induce normality (usually) which is important for certain statistical tests.
   
   
  Bill Shannon, PhD
Associate Professor of Biostatistics in Medicine
Washington University School of Medicine
http://ilya.wustl.edu/~shannon 

Founder and President
BioRankings, LLC
314-704-8725



Benjamin Otto <b.otto@uke.uni-hamburg.de> wrote:
  Hi,

Just a stupid statistical question to z-scores:

Given a set "S" of numeric values the z-score of these values is given by:

(S - mean(S))/sd(S)

??? What range of values do I expect afterwards? -1 to 1 mainly? When my
standard deviation is smaller than one, then I get my range scaled up rather
than down, but in any case and that is the main thing my standard deviation
is scaled to 1. So do I have to worry if my new value range is scaled up?

Benjamin

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