II. Graphing Distributions


  1. Introduction
  2. Qualitative Variables
  3. Quantitative Variables
    1. Stem and Leaf Displays
    2. Histograms
    3. Frequency Polygons
    4. Box Plots
    5. Box Plot Demonstration
    6. Bar Charts
    7. Line Graphs
  4. Exercises
  5. PDF Files (in .zip archive)

Graphing data is the first and often most important step in data analysis. In this day of computers, researchers all too often see only the results of complex computer analyses without ever taking a close look at the data themselves. This is all the more unfortunate because computers can create many types of graphs quickly and easily.

The introductory section of this chapter gives an example in which a well-construed graph makes it clear that there was a bias in the draft lottery of 1969. The two following sections discuss common graphs for qualitative and quantitative variables.