How to do it...

If you are using RStudio, the following three steps will get you ready to roll:

1. Launch RStudio on your computer.
2. At the R console prompt, install the three R packages needed for this project:

install.packages("plyr") 
install.packages("ggplot2") 
install.packages("reshape2") 

1. Load the R packages as follows:

library(plyr) 
library(ggplot2) 
library(reshape2)