Data Analysis with R, Second Edition - Second Edition

Two categorical variables

The visualization of categorical data is a grossly understudied domain and, in spite of some fairly powerful and compelling visualization methods, these techniques remain relatively unpopular.

My favorite method for graphically illustrating contingency tables is to use a mosaic plot. To make mosaic plots, we will need to install and load the VCD (Visualizing Categorical Data) package:

 install.packages("vcd") 
 library(vcd) 
 
 ucba <- data.frame(UCBAdmissions) 
 mosaic(Freq ~ Gender + Admit, data=ucba, 
         shade=TRUE, legend=FALSE)

After loading the preceding package the output obtained will be as follows:

Figure 3.10: A mosaic ...