R help - Apr 2009 - drawing a plot with SEM

I have a data matrix:
        repeat1    repeat2
1        30            34
2        12            23
3         50           13
4         56            98
.
.
.

I would like to plot for the mean and standard error of mean of repeat 1 and
repeat2 for each row.
Any pointers on how to do this in R?

TIA,
Anjan
-- 
============================anjan purkayastha, phd
bioinformatics analyst
whitehead institute for biomedical research
nine cambridge center
cambridge, ma 02142

purkayas [at] wi [dot] mit [dot] edu
703.740.6939

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Assume the object in question is a dataframe named "dm":

apply(dm, 1, mean)

It worries me that you are asking for the sem's of two element  
objects, but if you really want it, the obvious modification to the  
above should work.


On Apr 22, 2009, at 10:26 AM, ANJAN PURKAYASTHA wrote:
> I have a data matrix:
>        repeat1    repeat2
> 1        30            34
> 2        12            23
> 3         50           13
> 4         56            98
> .
> .
> .
>
> I would like to plot for the mean and standard error of mean of  
> repeat 1 and
> repeat2 for each row.
> Any pointers on how to do this in R?
>
> TIA,
> Anjan
> -- 
> ============================> anjan purkayastha, phd
> bioinformatics analyst
> whitehead institute for biomedical research
>
David Winsemius, MD
Heritage Laboratories
West Hartford, CT

I realized after looking again that you asked for plotting. Since you  
only have two points per row, it would be more honest statistically to  
plot the values rather than mean and sem.

 > dm <-read.table(textConnection("      repeat1    repeat2
+ 1        30            34
+ 2        12            23
+ 3         50           13
+ 4         56            98"), header=TRUE)
 > plot(x=1:nrow(dm), y=dm$repeat1, ylim=c(min(dm), max(dm))  )
 > points(x=1:nrow(dm), y=dm$repeat2)


On Apr 22, 2009, at 10:26 AM, ANJAN PURKAYASTHA wrote:
> I have a data matrix:
>        repeat1    repeat2
> 1        30            34
> 2        12            23
> 3         50           13
> 4         56            98
> .
>
> I would like to plot for the mean and standard error of mean of  
> repeat 1 and
> repeat2 for each row.
> Any pointers on how to do this in R?
>
> TIA,
> Anjan
> -- 
> ============================> anjan purkayastha, phd
> bioinformatics analyst
> whitehead institute for biomedical research
David Winsemius, MD
Heritage Laboratories
West Hartford, CT