4. (5 points, show codes only} Propose a model to examine tax fees. Write down your dependent variable (Y) and independent variables [Ks]. Show your codes on how to generate these variables. The independent variables should have some economic meanings and comparable across firms. Briefly explain what firm characteristics each independent variable is used to measure. 5. [3 points, show both codes and results] Run the regression model you proposed for tax fees and report the results. 6. (2 point} Briefly comment on what you find based on results reported in Question 5. Hint: focus on the positive and negative relation between Xs and Y, and whether the coefficients are statistically significant