R help - Oct 2011 - Correlation Matrix in R

Hi, 

I am currently working with a data set which contains a list of julian dates
of phenological (flowering, leaf growth etc.) 

I obtained a correlation matrix by simply using the cor function with the
dataset cor(dataset,use="complete.obs")

that gives me a correlation matrix but the correlations are somehow
different from when I run individual correlations using the cor function and
the same correlation method.  When a smaller sub data set (3 columns) is
created from the original (27 colums) this does NOT occur!

I am a little confused by this, 
If anyone knows the reason please let me know.
Otherwise I'm looking for another way to get a correlation matrix.  I do not
know how to write a loop function to do individual correlations

Thank you for your help.

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I believe it has to do with the "complete.obs" choice and the presence
of NAs in your data. The differences should vanish with
"pairwise.complete.obs" but whether that's what you want is up to
you.


Michael

On Tue, Oct 25, 2011 at 5:09 PM, AlexC <alexandre.chausson at unil.ch>
wrote:
> Hi,
>
> I am currently working with a data set which contains a list of julian
dates
> of phenological (flowering, leaf growth etc.)
>
> I obtained a correlation matrix by simply using the cor function with the
> dataset cor(dataset,use="complete.obs")
>
> that gives me a correlation matrix but the correlations are somehow
> different from when I run individual correlations using the cor function
and
> the same correlation method. ?When a smaller sub data set (3 columns) is
> created from the original (27 colums) this does NOT occur!
>
> I am a little confused by this,
> If anyone knows the reason please let me know.
> Otherwise I'm looking for another way to get a correlation matrix. ?I
do not
> know how to write a loop function to do individual correlations
>
> Thank you for your help.
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Correlation-Matrix-in-R-tp3938274p3938274.html
> Sent from the R help mailing list archive at Nabble.com.
>
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