Analysis of variance (
ANOVA) is a collection of
statistical models used to analyze the differences among group means and their associated procedures (such as "variation" among and between groups), developed by
statistician and
evolutionary biologist Ronald Fisher. In the ANOVA setting, the observed
variance in a particular variable is partitioned into components attributable to different sources of variation. In its simplest form, ANOVA provides a
statistical test of whether or not the
means of several groups are equal, and therefore generalizes the
t-test to more than two groups. ANOVAs are useful for comparing (testing) three or more means (groups or variables) for
statistical significance. It is conceptually similar to
multiple two-sample t-tests, but is less conservative (results in less
type I error) and is therefore suited to a wide range of practical problems.