Which model? This exercise concerns the optional material in Section 9.2 on models for two-way tables. Look at Exercises 9.10, 9.12, 9.16, 9.28, and 9.30. For each exercise, state whether you are comparing several populations based on separate samples from each population (the first model for two-way tables) or testing independence between two categorical variables based on a single sample (the second model).