[R] calculating percent error from 2 vectors

[Greg Snow]

Try something like:

> mytable <- table(known, modelout)
> prop.table( mytable, 1 )

Also look at ?addmargins and the CrossTable function in the gmodels
package.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 
 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Scott Bearer
> Sent: Thursday, July 12, 2007 11:32 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] calculating percent error from 2 vectors
> 
> Hello,
> 
> I believe this is an easy scripting problem, but one I am 
> stumbling on.
> 
> I have a "known" vector of 3 colors with nrow=10:
> known<-c("red", "blue", "red", "red", "yellow", "blue", 
> "yellow", "blue", "blue", "yellow")
> 
> and a model output vector:
> modelout<-c("red", "red", "red", "blue", "yellow", "blue", 
> "blue", "red", "blue", "yellow")
> 
> I would like to determine the proportion (in)correctly 
> identified for each color.  In other words:
> % correct "red"=
> % correct "blue"=
> % correct "yellow"=
> 
> How would I code this (assuming the actual dataset is more complex)?
> 
> Any help would be much appreciated.
> 
> Thank you,
> Scott
> 
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