Class 8 (Module II)

6 Abril 2022, 15:00 • Jorge Filipe Campinos Landerset Cadima

[Slides 243-297] One-way ANOVA: the model with the assumptions that make it a Linear Model. The F test for factor effects as a goodness-of-fit test of the Linear Model: adaptations of the terminology and notation; fitted values as the level means; the formulas for Factor and Residual Sums of Squares and Mean Squares; the Linear Model decomposition and the origin of the name 'Analysis of Variance'; the summary table. One-way ANOVAs in R and an example with the iris data. Some additional comments on one-way ANOVAs. A brief discussion of issues in experimental designs: randomization, independent repetitions and pseudo-repetitions, controlling the heterogeneity of experimental units through the introduction of additional factors (blocks) to control variability. Two-way factorial designs: the concept and some issues of notation and terminology. A first model for two-way ANOVAs, without interaction effects: the model, the need for two tests, the two F tests, some formulas (for balanced designs) and the summary table. A discussion of the two alternative approaches (exchanging factors A and B) and their difference when the design is not balanced. Fitting the two-way ANOVA model without interaction with R and a classic example.
Nota: Esta aula foi leccionada na quarta-feira, dia 20.4.22, das 15h às 17h45, na Sala S3, simultaneamente presencial e por zoom.