Hi All,

I need a small help plotting median lines on lattice boxplots.

# Data
a <- rep(c("A","B"), each=10)
b <- rep(c("a","a+b","b","b+a"), each=5)
c <- c(1,9,5,2,7,7,8,8,8,5,4,5,3,2,5,6,7,8,9,1)
x <- data.frame(a, b, c)
med.A <- median(subset(x$c, x$a=="A"))
med.B <- median(subset(x$c, x$a=="B"))

median(group A) = 7
median(group B) = 5

I need help to plot two (horizontal) lines, one for each subgroup.
- Line 1 coordinates should be (0, 7) to (2.5, 7)
- Line 2 coordinates should be (2.5, 5) to (5, 5)

I'm unable to control the length of these lines, can anyone please help me
with this, I would highly appreciate any help. (I tried using panel.curve,
but of no use)

# Plotting code:
library(lattice)

bwplot(c ~ b, data = x,
   panel = function(...)
   {
      panel.abline(v=2.5, col.line="gray")
      panel.bwplot(...)
   }
)

Thank in advance,

-- 
Xin Ge.

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