Other
Getting to the Point With Interest Based Negotiations
This site defines interest-based negotiation, gives an example, and provides five good negotiation habits.
Purple Math
Purplemath: Quartiles, Boxes, and Whiskers
Explains how to construct a simple box-and-whisker plot, and demonstrates the steps. Discusses quartiles and medians, shows how to find them, and explains how they relate to box-and-whisker plots.