Charts and Graphics
R includes several packages for visualizing data:
lattice. Usually, you’ll find that functions
lattice packages are the most
useful. If you’re familiar with Microsoft Excel, you’ll find
that R can generate all of the charts that you’re familiar with:
column charts, bar charts, line plots, pie charts, and scatter plots.
Even if that’s all you need, R makes it much easier than Excel to
automate the creation of charts and customize them. However, there are
many, many more types of charts available in R, many of them quite
intuitive and elegant.
To make this a little more interesting, let’s work with some real data. We’re going to look at all field goal attempts in the National Football League (NFL) in 2005. For those of you who aren’t familiar with American football, here’s a quick explanation. A team can attempt to kick a football between a set of goalposts to receive 3 points. If it misses the field goal, possession of the ball reverts to the other team (at the spot on the field where the kick was attempted). We’re going to take a look at kick attempts in the NFL in 2005.
First, let’s take a quick look at the distribution of distances.
R provides a function,
hist, that can do
this quickly for us. Let’s start by loading the appropriate data set.
(The data set is included in the
nutshell package; see
the Preface for information on how to obtain this
> library(nutshell) > data(field.goals)
Let’s take a quick ...