In this chapter, you learned some more of the basic syntax and techniques of producing graphs in R. We discussed more on regression lines and residuals—creating complex multiple axes, superposing graphs, labeling points on your graph, creating grid lines, shading and coloring graphs using the polygon() command, and so on. I hope this chapter provided a range of useful techniques in addition to those that you learned in the previous chapter.

The next chapter will continue from where we left off in this chapter. In the next chapter, we will learn how to create graphs using qplot, a very powerful graphics command that is available through the ggplot package.