R help - Feb 2003 - coplot with boxplot panel function

I am attempting to construct a conditioning plot with a pair 
of boxplots within each panel.  The resulting plot has panels 
misplaced.  One misplaced panel is on top of the subcomponent 
describing ranges of the conditioning variable.  This is what I did:

X <- cut(rnorm(200), 2)
Y <- runif(200)
Z <- rnorm(200)
given.Z <- co.intervals(Z, number = 4, overlap = .25)

coplot(Y ~ X | Z, given.v = given.Z,
panel = function(x, y, ...){boxplot(y ~ x)})

   Any suggestions as to why this does not work and what the 
correct specification is would be greatly appreciated.

thanks,

Chuck Cleland

WinXP Pro

 > version
          _
platform i386-pc-mingw32
arch     i386
os       mingw32
system   i386, mingw32
status
major    1
minor    6.2
year     2003
month    01
day      10
language R

Chuck Cleland wrote:
>   I am attempting to construct a conditioning plot with a pair of 
> boxplots within each panel.  The resulting plot has panels misplaced.  
> One misplaced panel is on top of the subcomponent describing ranges of 
> the conditioning variable.  This is what I did:
> 
> X <- cut(rnorm(200), 2)
> Y <- runif(200)
> Z <- rnorm(200)
> given.Z <- co.intervals(Z, number = 4, overlap = .25)
> 
> coplot(Y ~ X | Z, given.v = given.Z,
> panel = function(x, y, ...){boxplot(y ~ x)})
> 
>   Any suggestions as to why this does not work and what the correct 
> specification is would be greatly appreciated.
> 

Not sure, but you might want to try boxplot(y ~ x, add = TRUE).

When I did this I had to add xlim = c(0, 3) so the boxplots were drawn 
completely within the panel.

Sundar