[R] How to add a line of "mean" to the bwplot (lattice package)

[Bert Gunter]

Jun:

Call a custom panel function that adds horizontal lines at the means
of your groups. Something like (for vertical boxes, i.e.horiz=FALSE;
make appropriate change for horizontal boxes)

e.g.

panel.mn <- function(x,y,box.width=.5,horiz=FALSE,...){
  panel.bwplot(x,y,box.width,horiz=horiz,...)
  y <- tapply(y,x,mean,na.rm=TRUE)
  x <- seq_along(y)
  panel.segments(x0=x-box.width/2,x1=x+box.width/2,
                 y0 = y,y1=y,...)
}

bwplot(your.y ~ your.x, panel=panel.mn,...)

## where ... means more arguments specifying colors, bwplot
parameters, etc. if desired

Cheers,
Bert





Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
Clifford Stoll




On Sun, Jan 25, 2015 at 7:06 AM, Jun Shen <jun.shen.ut at gmail.com> wrote:
> Dear list,
>
> The bwplot generates box plots with a dot in median. How do I add a line of
> "mean" to the boxes? Thanks a lot.
>
> Jun
>
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>
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