[R] Is there a function for this?

[Andreas Hary]

Try the following:

act <- c('good','good','bad','bad','good','good','bad','bad')
pred <- c('good','bad','bad','bad','good','good','good','bad')
table(pred,act)
table(pred,act)/apply(table(pred,act),1,sum)

Cheers,

Andreas


On 1/3/07, Feng Qiu <hustqiufeng at sohu.com> wrote:
> Hi everybody, I'm trying to do a statistic on the error rate of a prediction
> algorithm.
>
> suppose this is the real category
> [good, good, bad, bad, good, good, bad, bad]
> this is the predicted category
> [good, bad, bad, bad, good, good, good, bad]
>
> I'm trying to do a statistic on the error rate for each group("good","bad"):
> what percentage of instances are predicted incorrectly for each group ?
> Of course I can write a loop to do that, but is there a easy way to do that?
>
> Thank you!
>
> Best,
>
> Feng
>
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