(3d) Consider the R-squared of the second stage regression. Do you feel that the explanatory variables do a good job of explaining the variation in real incomes per capita in the sample? How does the R-squared here compare to the R-squared from regression in Problem Set 5, question 2? (3e) Comment on the validity of interpreting the estimated effect of fitted protection from expropriation as a causal effect of institutions upon real income per capita. Do you feel that the TSLS procedure employed here (advocated by AJR) effectively addresses the standard threats to valid inference? Are you convinced by their argument? What are some possible policy implications of their finding