ANOVA is a statistical technique that assesses potential differences in a scale-level dependent variable by a nominal-level variable having 2 or more categories. Developed by Ronald Fisher in 1918, this test extends the t and the z test which have the problem of only allowing the nominal level variable to have two categories. This test is also called the Fisher analysis of variance.
There are three primary assumptions in ANOVA:
1. The responses for each factor level have a normal population distribution. 2.These distributions have the same variance.
3.The data are independent.