- The distinction between fixed and stochastic regressors. - Data analysis with (nonorthogonal) ANOVA (SPSS): Type I, II, III, and IV of decomposing the sum of squares. All of them do not test the hypothesis that the average treatment effect is zero. - Hypotheses that are tested as the so-called main effects with Typ I, II, and III. - Summarizing the basic concepts and equations in the analysis of conditional and average effects.