Computer lab 11: Balanced Two-way ANOVA
In one-way ANOVA we study the relationship between one response variable and one explanatory
factor (with several factor levels). Now we extend the model to two explanatory factors and want to
study the relationship to each factor and to the combination of them.
Learning objectives
After reading the recommended text and completing the computer lab the student shall be able to:
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Formulate a two-way ANOVA model in two different ways and explain how the model
parameters can be interpreted
Understand the interaction concept
Use data sets to make inference about the model parameters
Use the procedures Two-way and Balanced Anova in Minitabs ANOVA (or perhaps similar
procedures in another software)
Recommended reading
Chapter 19 in Kutner et al
Assignment 1: Model validation
Solve exercise 19.12abc and extend c to all relevant residual plots, histogram for residuals etc.
Comment the results. Is the model adequate for these data?
Use Minitabs Two-way for these analyses.
Assignment 2: Standard analysis
Solve exercise 19.13abcdf. Use both Two-way and Balanced ANOVA for the analysis.
Assignment 3: Comparisons
Solve exercise 19.31abcef.
It is interesting to compare all 4 cell means pairwise (why?). Use Tukeys method with simultaneous
confidence coefficient 95 % (utilize One-way for this analysis).
To hand in
Solutions to all three assignments, no later than Wednesday 13th of November.