Multivariate Visualization

A picture is worth a thousand words. This may be especially true in statistics. While plotting univariate or even bivariate data is not too difficult, and we can learn much from such plots, multivariate data is much more difficult to visualize effectively. We often have a number of variables in a data set and we want to learn as much as we can about their relationships. We explore some techniques here.

One reason why many data analysts use R is because R can create graphics that are both informative and visually appealing without too much effort or time (if you use the right packages and know what you are doing). We will explore methods for visualizing multivariate data using three dominant plotting tools: base R plotting, plotting using the lattice package, and plotting using the ggplot2 package.