Statistical Inference

# The Analysis of Variance Procedure

Please select the aspect of the Analysis of Variance (ANOVA) procedure you would like practice with:

The Analysis of Variance (ANOVA) is used to determine if the means of several subgroups are the same. Using this procedure, you can only test a hypothesis regarding the equality of the several μi. In order to use ANOVA, the following assumptions must be met:

1. The data come from a Normal distribution
2. The variances of the several populations are the same

These assumptions are in addition to the usual two assumptions that the sample is representative of the target population and that the sample values are independent.

If any of these assumptions are not met, then this is not the appropriate procedure to use. Note, however, that ANOVA is rather robust to violations of Normality and that adjustments can be made when the variances are not equal.