A book devoted to a single statistical test may seem excessive, but Analysis of Variance is more a collection of data analysis techniques than a single statistical test. In trained hands, they are extremely powerful and can make sense of the most convoluted data sets, but in untrained hands they can occasionally be dangerous. However, we will be starting at the basics and working forwards slowly. Although formulae and worked examples are given, we will keep the numbers of subjects and the scores low, simplifying the worked examples. In the first two chapters, we will begin by revising the most important topics that you were taught on your introductory courses. We will then discuss experimental designs in which a single independent variable can have three or more levels, and then designs with more than one independent variable. Hence, if you have ever been frustrated by being restricted to trying studies with one independent variable and two levels, or have been forced to choose between two alternative independent variables when you would have preferred to try both, then you will find the scope of these more advanced statistical tests to be liberating. However, first we must start with the basics, and to begin with we will recap on some of the key phrases that the remainder of the book will assume you are familiar with.