(f) Suppose 12 =2x1 +3. i. [3 marks] Write down the information matrix, XX for the Model 2. ii. [1 mark] What property that can be observed in 2"d and 3"d columns (rows) for the XX matrix? (g) [2 marks] Now suppose r = r; is a continuous covariate and 12 = 1, is a binary covariate. Which model/models would be changed, if any? Write down the model/models in terms of r; and z; that would be changed, if any? (h) [2 marks] Now suppose r is a categorical covariate with three categories. Suppose we fit a multiple regression model that is a quadratic. Which model/models would be the most appropriate to depict in this case, if any? Explain briefly