It would be easier to diagnose the problem if you included an example
illustrating exactly what you did.  I'll guess:

> a <- list(3,4,5)
> mean(a)
[1] NA
Warning message:
In mean.default(a) : argument is not numeric or logical: returning NA

> mean(as.numeric(a))
[1] 4

But that's just a guess, as I don't know the actual contents of your list!

albyn


On Fri, Aug 30, 2013 at 5:18 AM, agnes69 <festre@gredeg.cnrs.fr> wrote:

> When I try to apply mean to a list, I get the answer :
>
> argument is not numeric or logical: returning NA
>
> Could you help me?
>
> (I am a very beginner)
>
>
>
> --
> View this message in context:
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