[R] normalizing data sets
Martin Hoyle
plxmh at nottingham.ac.uk
Tue Oct 15 14:05:58 CEST 2002
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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