ANalysis Of VAriance (ANOVA), or F-test, is an extension of the independent groups t-test. Analysis of variance is a more general statistical procedure than the groups t-test. You will remember that the t-test was used when we had two levels of the independent variable (males and females) and we wanted to see how the groups differed on a interval/ratio variable. However, often there are categorical variables which have more than two levels. In the Crime dataset, for instance, these include social class (rrgclass), religion (religion) and educational qualifications (hedqual). Analysis of Variance is similar to the independent groups t-test; only it is when there are more than two levels of an independent variable.