adding spread data to dotplots in R

Question

I have a table with averages and interquartile ranges. I would like to create a dotplot, where the dot would show this average, and a bar would stretch through the dot, to show the interquartile range. In other words, the dot would be at the midpoint of a bar, the length of which would equal my interquartile range data. I am working in R.

For example,

labels<-c('a','b','c','d')
averages<-c(10,40,20,30)
ranges<-c(5,8,4,10)
dotchart(averages,labels=labels)

where the ranges would then be added to this plot as bars.

Any ideas?

Thanks!

Answer 1

Yet another method, using base.

labels <- c('a', 'b', 'c', 'd')
averages <- c(10, 40, 20, 30)
ranges <- c(5, 8, 4, 10)
dotchart(averages, labels=labels, xlab='average',  pch=20,
         xlim=c(min(averages-ranges), max(averages+ranges)))
segments(averages-ranges, 1:4, averages+ranges, 1:4)

Answer 2

For the record, here's a lattice solution, which uses a couple of functions from the Hmisc package:

library(lattice)
library(Hmisc)

labels<-c('a','b','c','d')
averages<-c(10,40,20,30)
ranges<-c(5,8,4,10)
low  <- averages - ranges/2
high <- averages + ranges/2
d <- data.frame(labels, averages, low, high)

Dotplot(labels ~ Cbind(averages, low, high), data = d, 
        col = 1,                                        # for black points
        par.settings = list(plot.line = list(col = 1)), # for black bars
        xlab = "Value")