[R] Principle Component Analysis in R

[Jari Oksanen]

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 at sun3.oulu.fi>