anova (thing)

An abbreviation for analysis of variance. ANOVAs are like t-tests except potentially much more complicated. In psychology and I suspect in many other sciences, an ANOVA is typically used in the following manner:

• Assign some subjects to different groups randomly.
• Do one thing to group A and another, slightly different thing to group B.
• Measure some performance of both groups.
• Compare the mean performance using an ANOVA to see if they differ.

ANOVA is nice because you can do multiple kinds of groupings and see the interaction of them. Consider the following hypothetical experiment:

1. Group 1 was not fed cheese and not hit with a hammer.
2. Group 2 was not fed cheese and was hit with a hammer.
3. Group 3 was fed cheese and not hit with a hammer.
4. Group 4 was fed cheese and was hit with a hammer.

Using a two-way ANOVA, you can determine not only the effects of being fed cheese on your outcome and being hit with a hammer, but whether there are any interactions of being fed cheese and being hit with a hammer that cannot be explained merely as the sum of the effects of being fed cheese and being hit with a hammer.