Pie Chart

A pie chart of a qualitative data sample consists of pizza wedges that shows the frequency distribution graphically.

Example

In the data set painters, the pie chart of the School variable is a collection of pizza wedges showing the proportion of painters in each school.

Problem

Find the pie chart of the painter schools in the data set painters.

Solution

We first apply the table function to produce the frequency distribution of School.

> library(MASS)                 # load the MASS package
> school = painters$School      # the painter schools
> school.freq = table(school)   # apply the table function

Then we apply the pie function to produce its pie chart.

> pie(school.freq) # apply the pie function

Answer

The pie chart of the school variable is:

Enhanced Solution

To colorize the pie chart, we select a color palette and set it in the col argument of pie.

> colors = c("red", "yellow", "green", "violet",
+   "orange", "blue", "pink", "cyan")
> pie(school.freq,             # apply the pie function
+   col=colors)                # set the color palette

Exercise

Find the pie chart of the composition scores in painters.

Tags:

An R Introduction to Statistics