How to put Values on Boxplot in R for several boxplot in one image

Question

I want to plot Delta~Project.Types in R. I have 10 Project Types. I know how to do the boxplot : boxplot(Delta~Project.Types). However, how can I put the fivenum (min, max,

Answer 1

The stats you want can also be obtained with fivenum

five <- by(InsectSprays$count, InsectSprays$spray, fivenum)
do.call(cbind, five)
#         A    B   C    D   E  F
# [1,]  7.0  7.0 0.0  2.0 1.0  9
# [2,] 11.0 12.0 1.0  3.5 2.5 12
# [3,] 14.0 16.5 1.5  5.0 3.0 15
# [4,] 18.5 18.0 3.0  5.0 5.0 23
# [5,] 23.0 21.0 7.0 12.0 6.0 26

Alternatively, these stats are one of the return values of boxplot (note that you need to use range = 0 to get the min and max since there are some values which are outlying):

bp <- boxplot(count ~ spray, data = InsectSprays, col = "lightgray", range = 0)
bp$stats
#      [,1] [,2] [,3] [,4] [,5] [,6]
# [1,]  7.0  7.0  0.0  2.0  1.0    9
# [2,] 11.0 12.0  1.0  3.5  2.5   12
# [3,] 14.0 16.5  1.5  5.0  3.0   15
# [4,] 18.5 18.0  3.0  5.0  5.0   23
# [5,] 23.0 21.0  7.0 12.0  6.0   26

Then just add to each box:

text(x = col(bp$stats) - .5, y = bp$stats, labels = bp$stats)

Answer 2

You can add a "legend" to a base R plot that contains what you want like this:

legend("topright", bty = "n", legend = summary(Delta))

I'm assuming that it's "Delta" that you're running summary() on, so change that as needed. You can modify the appearance of what shows up in the legend using paste(), i.e.

legend("topright", bty = "n", legend = c(paste("min =", summary(Delta)[1]),
                                     paste("max =", summary(Delta)[2])))

etc.