[R] summary with variance / sd

[Stephan Kolassa]

Hi Jörg,

?by

here probably something like

by(data=mydata,INDICES=mydata$group, FUN=sd, ...)

HTH,
Stephan


Jörg Groß schrieb:
> Hi,
> 
> I have a data frame and would like to have summary statistics for 
> grouped data.
> 
> With summary() I get the central tendencies for the overall data.
> 
> 
> How can I get descriptive statistics with variances and standard 
> deviations?
> 
> 
> for example my data.frame:
> 
> group    x    y
> exp        2    4
> exp        3    5
> exp        2    4
> control    1    2
> control    2    3
> control    1    2
> 
> 
> now I want tables with summary statistics (variances included) for each 
> group.
> 
> Is there an easy way to get this?
> 
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