[R] outlier detection methods in r?

[Robert L. Sandefur]

hi -

 if I sample from a normal distribution with something like
n100<-rnorm(100,0,1)
and add an outlier with 
n100[10]<-4
then
qqnorm(n100)
visually shows the point 4 as an outlier
and calculating the probablity of a value of 4 or bigger  in 100 samples of norm(0,1)
gives
> 1-exp(log(pnorm(4,0,1))*100)
[1] 0.003162164

If I have more than 1 sample above outlier threshold the math is a bit more complicated
but doable.

My questions are 

1) are there better ways to assess probablity of outliers (ie value(s) above theshold from a given distribution)?
2) are they implimented in r?

(I checked outlier and extreme in r help and found nothing helpful)

thanx

bob sandefur

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