[R] boxplot with grouped variables

[Bert Gunter]

It will not work because the presence of the first row means that all
the variables are read in as factors, not numeric. You must convert
numeric variables to numeric **after** eliminating the first row, or
read the data in using read.table(..., head=TRUE). See ?read.table for
details.

**After** the above changes, perhaps

with(Daten, boxplot(Gewicht ~ interaction(Dosis,Geshlecht, drop=TRUE)) )

will work if you read in column names properly. Otherwise, V2
~interaction(V1,V3, drop=TRUE) if you do the conversions to numeric.

Please read *An Introduction to R" or other online R tutorial before
posting further here. You need to understand basic R data handling
before you proceed. At present, you do not.

-- Bert



On Sat, May 11, 2013 at 8:40 AM, maggy yan <kiotoqq at gmail.com> wrote:
> my dataset looked like this in the beginning:
>
>>Daten
>       V1      V2         V3
> 1  Dosis Gewicht Geschlecht
> 2      0    6.62          m
> 3      0    6.65          m
> 4      0    5.78          m
> 5      0    5.63          m
>
> I need box plots for V2 with all combination of V1 and V3, so I deleted the
> first row, and tried this:
> boxplot(Daten$V2[Daten$V3=="m"])
> but it does not work and I have no clue what I did wrong.
> I'm thankful for any help!
>
>         [[alternative HTML version deleted]]
>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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