(c) Stefan considers comparing test scores for students with last names in the first half of the alphabet to test scores for students with last names in the second half of the alphabet. He consults you for advice on this proposed evaluation strategy. Do you think this would yield plausible results? (5 points) (d) Now suppose that, since Stefan gets more tired as he grades more problem sets, he always needs a break after grading the first thirty (Alphonso-Gibbs through Liu), and he starts grading the rest (Maralet through Zhu) after being fully refreshed. Stefan considers using a regression discontinuity design to evaluate the impact of homework feedback on test scores using last names L-M as the cutoff. He consults you for advice on this proposed evaluation strategy. Do you think this would yield plausible results? (5 points)