Visualizing Categorical Data
ABSTRACT There are several graphical methods for quantitative data that are well- developed and widely used in both analysis and presentation of data. How- ever, graphical methods for categorical data are only now being developed but are not widely used. This paper outlines the use of the 'vcd' package in R which focuses on visualization techniques, data sets, summary and infer- ence procedures aimed particularly at categorical data. Inherently, this study aims to test the capabilities of the 'vcd' package by using it analyze the real world data by making use of: cotabplot, fourfold, mosaic plot, spline and cd-plot with special emphasis given to highly extensible grid graphics. These methods make it possible to analyze and visualize the association between a large number of categorical data. R codes for the various plots are provided.