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Suppose you want to include an attribute representing the interaction between two other attributes (let's call then X2 and X3) into a linear model. How would you include their interaction in a linear model for regression? By adding an attribute calculated as X2 X3 into the model. By adding two attributes calculated as X2*2 and X3^2 into the model. Interaction between features cannot be included in a linear model for regression. By adding an attribute calculated as X2 * x3, and removing X2 and X3 from the model