[BioC] PCA scree plot question

Naomi Altman naomi at stat.psu.edu
Tue Jun 16 17:34:13 CEST 2009


The fun thing about eigenvalues is that they are linear combinations 
of ALL the genes.

At 10:54 AM 6/16/2009, you wrote:
>Oh right, is there any way to figure out how many genes are involved
>in the component or does that even make sense?
>
>On Tue, Jun 16, 2009 at 3:39 PM, Naomi Altman<naomi at stat.psu.edu> wrote:
> > Y=variance of component
> >
> > units are measurement units^2
> >
> > --Naomi
> >
> > At 10:05 AM 6/16/2009, you wrote:
> >>
> >> Can anyone tell me what the units of the numbers on the Y-axis of the
> >> PCA plot are? I think its the number of genes involved in that
> >> particular component but maybe someone can tell me for sure? See here
> >> for an example of what I'm talking about:
> >>
> >> http://frink.nuigalway.ie/~pat/PCAScreePlotNorm.pdf
> >>
> >> Thanks alot,
> >>
> >> -Paul.
> >>
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> >
> > Naomi S. Altman                                814-865-3791 (voice)
> > Associate Professor
> > Dept. of Statistics                              814-863-7114 (fax)
> > Penn State University                         814-865-1348 (Statistics)
> > University Park, PA 16802-2111
> >
> >

Naomi S. Altman                                814-865-3791 (voice)
Associate Professor
Dept. of Statistics                              814-863-7114 (fax)
Penn State University                         814-865-1348 (Statistics)
University Park, PA 16802-2111



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