How to display the median value in a boxplot in ggplot?

Question

I am trying to show the median value(i.e the horizontal bar) in the a box plot by using ggplot(). R keeps asking to specify y axis. I am a bit stuck.

p <-         


        

Answer 1

I don't think that stat_bin is the way to go:

library(plyr)
library(ggplot2)

p_meds <- ddply(p, .(TYPE), summarise, med = median(TOTALREV))

ggplot(p,aes(x = TYPE, y = TOTALREV)) + 
    geom_boxplot() + 
    geom_text(data = p_meds, aes(x = TYPE, y = med, label = med), 
              size = 3, vjust = -1.5)

As a side note, I generally find that people are less confused with ggplot once they learn to stop using qplot.