Use the data in WAGEPAN.RAW for this problem. The data can be loaded with the TSP–program ‘datawagepan.tsp’, which also provides information on the variables. The data in WAGEPAN.RAW are from Vella and Verbeek (1998) for 545 men who worked every year from 1980 to 1987.
Consider the wage equation
      log(wageit) = θt + β1educi + β2blacki + β3hispani + β4experit +β5exper2 it + β6marriedit + β7unionit + ci + uit
Notice that education does not change over time.
   a) Estimate this equation by pooled OLS, and report the results in standard form. Are the usual OLS standard errors reliable, even if ci is uncorrelated with all explanatory variables? Explain. Compute appropriate standard errors.
   b) Estimate the wage equation by random effects. Compare your estimates with the pooled OLS estimates.
   c) Now estimate the equation by fixed effects. Why is experit redundant in the model even though it changes over time? What happens to the marriage and union premia as compared with the random effects estimates?
   d) Now add interactions of the form d81 · educ, d82 · educ, ..., d87 · educ and estimate the equation by fixed effects. Has the return to education increased over time? e) Return to the original model estimated by fixed effects in part c. Add a lead of the union variable, unioni,t+1 to the equation, and estimate the model by fixed effects (note that you lose the data for 1987). Is unioni,t+1 significant? What does this result say about strict exogeneity of union membership?
此题我们要求用stata解答，在a问中，如何判断sde的可信度？计算适当的sde？c问中为何exper为冗余？以及d问应该如何在stata上操作？在此谢谢了