[R] summary statistics for grouped data

Greg Snow Greg.Snow at imail.org
Fri Feb 12 18:36:57 CET 2010

There are several depending on what specifically you want to do.  Some of the things to look at include: tapply, aggregate, the plyr package.

Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of jose romero
> Sent: Friday, February 12, 2010 10:24 AM
> To: r-help at r-project.org
> Subject: [R] summary statistics for grouped data
> Hello list:
> Is there an easy way (preferably through one of the standard R
> packages) of obtaining summary statistics for grouped data? I could
> split the data into classes by hist, and then progressively calculate
> all the "columns" i need to obtain the mean and standard deviation, but
> i was looking for a single function that could do that with a data
> vector.
> Thanks in advance,
> jose romero
> 	[[alternative HTML version deleted]]
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