[R] - detecting outliers

[Rui Barradas]

Hello,

Had you looked more, and you would have seen R-help discussions on what 
is an outlier. Almost unanimously, an ill defined concept.

In your problem, predators don't eat all eggs that they are given except 
for one case, 38 were given and all 38 were eaten. You can detect this 
in R with

boxplot.stats(d$FR)

Or with the return value of boxplot. See ?boxplot

Hope this helps,

Rui Barradas

Em 07-06-2012 07:24, Joachim Audenaert escreveu:
> Hello all,
>
> I am estimating parameters for regression functions on experimental data.
> Functional response of Rogers type II.
>
> I would like to know which points of my dataset are outliers. What is the
> best method to do this with R?
> I found a method via R help, but would like to know if there are better
> methods for my purpose.
> Here is the script I us now:
>
> library("mvoutlier")
> dat <- read.delim("C:/data.txt")
> uni.plot(dat)
>
> My data looks like the following (copied into a txt file):
> (N0 is the initial number of eggs fed to the predator, FR is the number of
> eggs eaten by the predator during 24h)
>
> N0      FR
> 37      30
> 27      15
> 36      14
> 37      13
> 45      8
> 25      0
> 47      20
> 34      6
> 25      8
> 21      7
> 24      24
> 34      17
> 23      10
> 29      5
> 38      38
> 24      24
> 20      17
> 14      8
> 18      15
> 15      10
> 26      5
> 33      5
> 22      21
> 38      3
> 22      20
> 23      19
> 20      6
> 20      4
> 21      18
> 25      5
> 13      13
> 9       8
> 8       4
> 7       7
> 8       5
> 11      9
>
>
> Kind regards,
> Met vriendelijke groeten,
> Joachim
>
> Don't waste paper! Think about the environment before printing this e-mail
>
> ______________________________________
>
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