Statistics

You will need to understand and be able to calculate:

• Mean

• Median

• Mode

And understand:

• Standard Deviation.

Some links for more information about these topics:

• Robert Niles: Statistics every writer should know.
• Descriptive statistics from physics at the College of Saint Benedict/Saint John's University
• Introduction to statistics, Andrews University

or any basic statistics book. I'm sure they're available at the library. I'm sure there are a gajillion other websites of use, too.