This tutorial, directed primarily toward students doing research projects, is intended to help them do four things: (1) Decide if their data gathering activity can yield numerical data that will permit a meaningful hypothesis test. (2) If it will, decide if one of the tests described would be useful. (3) If so, apply that test, and (4) Adequately explain the use of the test so their readers can have confidence in their analysis. It is not intended to be a text for a complete statistics course - only a guide to few relatively simple tests . Complex hypothesis testing procedures are not...

Brutal warfare has been a constant companion of mankind. Sometimes rulers launch wars of aggression and those being attacked must defend themselves. At other times rival groups seem to go to war as a matter of course over wealth, religious differences, territory, or food supplies - or simply because they don't like each other much. Innovative use of even simple technology can trump weight of numbers. Superior technology can facilitate aggression or enable besieged societies to defend themselves. It can prevent conflict altogether. We look at the startling impact an innovation in weapon...