[BioC] PCA scree plot question

[Paul Geeleher]

So it doesn't make sense to say that subset of genes is exclusively
responsible for a single component? I take what you are saying to mean
that every gene contributes to every component but to a different
degree. I'll have to do some background reading on this PCA stuff...

On Tue, Jun 16, 2009 at 4:34 PM, Naomi Altman<naomi at stat.psu.edu> wrote:
> 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
>
>