State the multiple regression equation that predicts wine quality based on the percentage of alcohol and the type of wine (red, white). Interpret the meaning of the slopes b1 and b2. 10. At a 0.05 level of significance, determine whether each independent variable makes a contribution to the regression model. Then add an interaction term to the model and, again at a 0.05 level of significance, determine whether it makes a contribution to the regression model. Which model is the most appropriate? Explain.