please write all your answer on the paper.

6. The data set bwght.txt includes a sample of 1,388 newborns. The variables include: nt (a) Using OLS, estimate the equation log(bwghti)=0+1malei+2parityi+3log(faminci)+4packsi+ui (b) Why might packs be correlated with u ? Is cigprice likely to be a good instrument for packs? (c) Estimate the reduced form for packs and describe what the results imply about the identification of the equation in part (a) when using cigprice as an instrument for packs. (d) Using 2SLS, estimate the equation in part (a) using cigprice as an instrument for packs and discuss any important differences between the OLS and 2SLS estimates. (e) For the estimations in (a) and (d), perform a robust Wald test and a non-robust LM test of the significance of packs. Do your conclusions change by accounting for the potential endogeneity of packs using cigprice as an instrument? (f) Test for the endogeneity of packs using a Hausman test statistic. What do you conclude? 6. The data set bwght.txt includes a sample of 1,388 newborns. The variables include: nt (a) Using OLS, estimate the equation log(bwghti)=0+1malei+2parityi+3log(faminci)+4packsi+ui (b) Why might packs be correlated with u ? Is cigprice likely to be a good instrument for packs? (c) Estimate the reduced form for packs and describe what the results imply about the identification of the equation in part (a) when using cigprice as an instrument for packs. (d) Using 2SLS, estimate the equation in part (a) using cigprice as an instrument for packs and discuss any important differences between the OLS and 2SLS estimates. (e) For the estimations in (a) and (d), perform a robust Wald test and a non-robust LM test of the significance of packs. Do your conclusions change by accounting for the potential endogeneity of packs using cigprice as an instrument? (f) Test for the endogeneity of packs using a Hausman test statistic. What do you conclude