Problem 1. Consider a linear model to explain monthly beer consumption: beer = Bo + BIinc + Byprice + Bseduc + BAfemale + u, E[ulinc, price, educ, female] = 0 For the following forms of heteroskedasticity, write the transformed model you would use to estimate the parameters by WLS. (i) Var(ulinc, price, educ, female) = o2inc2 (ii) Var(ulinc, price, educ, female) = o2inc . price (iii) Var(ulinc, price, educ, female) = 02(female + (1 - female) . inc)