boxplot in subgroups

Hei,

the error message below just tells you that you have specified nine  
places along the axis where you want to have labels (i.e. at=1:9)  
but obviously you have only specified three labels (i.e. labels =  
c("C","M","S")). Thus, R is complaining that there are not enough  
labels for all positions. However, I guess from your description  
that you want to have only three labels below your plot, one for  
each group of three boxes that share the same ASA1 value. Thus, you  
could for example do like this:

axis(side=1,at=c(2,5,8),labels=c("C","S","M"))

Then you would get the label always below the middle one of the  
three boxes of each group.

Now the boxes are, however, still distributed evenly across the  
plot, but in case you want to have those that belong to the same  
subgroup a bit closer together, you can specify their position via  
the "at" option on the boxplot function (see ?boxplot).

An example with random data might look like this:

ASA1=factor(rep(c("C","S","M"),each=100))
ASA2=factor(rep(c("C","S","M"),100))
C1_C2=runif(300)
boxplot(C1_C2~ASA2*ASA1,xlim=c(0,12),at=c(1:3,5:7,9:11),xaxt="n")
axis(side=1,at=c(2,6,10),labels=c("C","S","M"))

See ?axis for further options, e.g. tcl=0 in case you don't want to  
have a tick at the axis at the position of the label.

Hope that helps,

Annette

Pooja Jain schrieb:

Hi,
I have data that looks like this:
ASA1    ASA2    C1_C2
C       M       9.0225
S       S       2.4315
M       C       3.4894
M       S       4.5282
C       M       1.3183
C       S       1.3735
S       C       1.0488
S       M       7.948
M       C       4.5827
I need to plot Boxplots for a given ASA1 (either C,S, or M) with  
respect to C1_C2. However, instead of one boxplot I want to plot  
three boxplots for a given ASA1 value such that each sub-boxplot  
represent the distribution for C1-C2 for each of the three possible  
values of ASA2 (C,S or M). I want to show this subgroup with a  
single xtics (either C, S or M) corresponding to the ASA1 value  
selected.
I tried to do it, but ending with the following error. I am not  
sure how exactly I should build the object to plot as subgroup.
Error in axis(side = 1, at = 1:9, labels = c("C", "M", "S" :
 'at' and 'labels' lengths differ, 9 != 3
In addition: Warning message:
In bxp(list(stats = c(1e-04, 2.82745, 6.0193, 10.5957, 22.2476,  :
 some notches went outside hinges ('box'): maybe set notch=FALSE
I would greatly appreciate any help in this matter.
Thank you.
-Kanu

-- 
Annette Heisswolf
Section of Ecology
Department of Biology
University of Turku
20014 Turku, Finland

phone	+ 358 2 333 6006
fax	+ 358 2 333 6550
mail	annette.heisswolf at utu.fi