This chapter provides a step-by-step introduction to creating graphs using qplot (a graphics tool within the ggplot2 package), and gives examples of functioning qplot code that can be adapted for many applications. The topics covered in this chapter are as follows:
Loading the
ggplot2package in order to useqplotUsing basic
qplotgraphics techniques and syntaxCreating scatterplots and line graphs
Mapping symbol size, type, and color to categorical data
Including regressions and confidence intervals in your graphs
Creating bar charts, histograms, boxplots, pie charts, and dotcharts
Creating time series graphs with dates
It is not possible to give a complete account of qplot in this book. However, by the end of this chapter, you should be able to use qplot to create a wide range of graphs for research and analysis.