Re: [R] Principle Component Analysis in R

From: Jari Oksanen <jarioksa_at_sun3.oulu.fi>
Date: Tue 05 Apr 2005 - 16:09:05 EST

On Tue, 2005-04-05 at 16:59 +1200, Brett Stansfield wrote:
> Dear R
> Should I be concerned if the loadings to a Principle Component Analysis are
> as follows:
>
> Loadings:
> Comp.1 Comp.2 Comp.3 Comp.4
> X100m -0.500 0.558 0.661
> X200m -0.508 0.379 0.362 -0.683
> X400m -0.505 -0.274 -0.794 -0.197
> X800m -0.486 -0.686 0.486 0.239
>
> Comp.1 Comp.2 Comp.3 Comp.4
> SS loadings 1.00 1.00 1.00 1.00
> Proportion Var 0.25 0.25 0.25 0.25
> Cumulative Var 0.25 0.50 0.75 1.00
>
> I just got concerned that no loading value was given for X100m, component
> 3. I have looked at the data using list() and it all seems OK

You don't have to worry about one empty cell in loadings: the print function (called behind the curtain to show the results to you) is so clever that it doesn't show you small numbers, although they are there. I guess this happens because people with Factor Analysis background expect this. However, I would be worried if I got results like this, and would not use Princip*al* Components at all, since none of the components seems to be any more principal than others. Wouldn't original data do?

cheers, jari oksanen

-- 
Jari Oksanen <jarioksa@sun3.oulu.fi>

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Received on Tue Apr 05 16:18:09 2005

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