For this question, you will need to run a modified version of the model specification you ran in Question 6. In particular, instead of including advertising expenditure for apples as a single regressor, I want you to allow the effect of advertising expenditures (the slope of the relationship between advertising expenditures and units sold) to be different if advertising expenditures is below 2.3, as compared to the case where it is above 2.3. Once you have run this regression, redo the prediction exercise from part 7. Does the result you get make more sense? Explain, using the plot from Question 2 to help support your