Describing Data and Distributions

David C. Howell

This page contains several things designed to help students think about distributions of variables.

• A set of data from Chatterjee, Handcock, and Simonoff (1995) on sexual activity among males and females provides the best example I have ever seen of how different measures of central tendency tell a different story. They also provide a nice example of a truly meaningful use of the mode.
  
• An SPSS program can easily be used to draw samples from various distributions and plot the resulting data. We can superimpose a normal distribution (Chapter6) to give a frame of reference. I have provided a simple syntax file for SPSS, but it could easily be modified for other software. This item is written up as a lab assignment, and can be modified as appropriate.
  
• We often talk about bimodal distributions, but we don't often see meaningful examples. An great example, which comes from geology, and not the social sciences, are some famous data on Old Faithful.
  
• It is somewhat easier to find positively skewed distributions, and a good example can be found at Mireault.html.
  
• An example of using descriptive statistics to get a handle on what the data have to say can be found in data from David Merrell on what happens when animals are raised under different kinds of music. This example illustrates a number of different points.

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Last revised: 6/30/98