# [R] normalizing data sets

Martin Hoyle plxmh at nottingham.ac.uk
Tue Oct 15 14:05:58 CEST 2002

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Martin Hoyle,
School of Life and Environmental Sciences,
University of Nottingham,
University Park,
Nottingham,
NG7 2RD,
UK
Webpage: http://myprofile.cos.com/martinhoyle

>>> "Rishabh Gupta" <rg117 at ohm.york.ac.uk> 10/14/02 05:19PM >>>
Hi,
Can someone tell me how to normalize a data set so that the mean of
the set is 0 and the variance is 1. As I understand, when you
calculate the principle components of a data set through correlation
as
< princomp( dataset,  cor=T ) >
then a similar calculation is performed. I would like to know how I can
perform such a calulation directly. Any help would be
greatly appreciated.

Many Thanks

Rishabh

Dear Rishabh,

Suppose your data was in variable x, with the following values;

x<-c(5,4,6,8,6,9,2,7,6,8)

Then create the variable xtransformed;

xtransformed<-(x-mean(x))/sd(x)

Then xtransformed has mean of 0 and variance of 1 as required;

mean(xtransformed) = 0,
var(xtransformed) = 1,

Regards,
Martin.

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