Question: Return to the wage regression discussed in the text. Empirical evidence shows that the wage-work experience (wasp) profile is concave - wages increase with work experience, but at a diminishing rate. To see if this is the case, one can add the wexp2 variable to the wage function (19.39). If wasp is treated as exogenous, so is wexp2. Estimate the revised wage function by OLS and IV and compare your results with those shown in the text.