Psy202: chapter 12 - introduction to analysis of variance (lecture 1 + 2) Anova can be used to compare two or more treatments. The goal of the analysis is to determine whether the mean differences observed among the samples provide enough evidence to conclude that there are mean differences among all the populations. We decide between two interpretations: there really are no differences between the populations (or treatments). Independent measures design means that there is a separate group of participants for each of the treatments. Factor 1: therapy technique: a separate group is used for each technique (independent measure) Each group is tested at three different times (repeated measures) Anova evaluate mean differences between two therapies an mean differences between scores obtained at different times: single-factor designs: studies that only have one independent variable. Independent-measures designs: studies that use a separate group of participants. The test statistic for anova is very similar to the independent-measures t statistic.