3. (8 points - 4 points each) The Marginal Rate of Return to Schooling (MRR) The following Table contains data on the discounted present value (at an interest rate of 5 percent) of life earnings for white men using data from the Current Population Survey 2015-2019. The last column on the right contains an estimate of the marginal rate of return per year of schooling using these raw data. Years Schooling PV Mean Years School MRR 4 Yrs Coll 1,576,324 18 0.095 a) Calculate the implied MRR for "some college, MRRsc. b) Explain briefly but precisely whether these data are consistent with a model in which all individuals have the same level of ability. HINT: What should be the slope of the MRR schedule, and why