Hello all
I am going to do a principal components analysis. I know that we can
standardise the variables (correlation-based PCA) to make them 'equally
important'.
I have read that
1)if we omitted standardisation, a variable which varied lot would tend to
dominate the principal components, and
2) standardisation to make variables equally important is suggested when the
variables are measured in different units.
My question is: if my variables are all measured in the same units (say
each variable contained scores for n people and each score could take one of
5 values 1 to 5), would it still be OK to do a correlation based PCA (i.e.
using covariance matrix of standardised variables) or would covariance based
PCA (I.e. using covariance matrix of unstandardised variables) be more
appropriate?
Many thanks, in advance for your help,
All the Best,
Kim.
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