ANALYSIS OF VARIANCE

The statistical technique used to test the null hypothesis that several population means are equal is analysis of variance (ANOVA). It is called that because it examines the variability in the sample and, based on the variability, it determines whether there is reason to believe the population means are unequal . We will be drawing conclusions about means by looking at variability.

All software statistical packages contain several different procedures that can perform analysis of variance. We will begin with the simplest format of ANOVA, which is the ONEWAY procedure. It is called one-way analysis of variance because cases fall into different groups based on their values for one variable.