6. Consider the following regression model: Y ~ P ctUnemployment + Region + Region . P ctUnemployment, (1) where Region is a categorical variable [Note: Variable 14 specifies the Pc- tUnemployment. Variable 17 specifies the geographic region] (a) Fit model (1) and write down the fitted equation. (You'll need to specify the dummy variables to write down the fitted equation.) (b) Based on the fitted model in (a), write down the equations for the 4 regions separately. (c) Test whether the lines for the 4 regions are coincident. That is, test for the significance of simultaneously adding Region and Region*PctUnemployment to a model already including PctUnemployment. State your hypothesis, test statistics and its value, p-value, and draw your conclusion based on the SAS output