(i) In the model with one endogenous explanatory variable, one exogenous explanatory variable, and one extra exogenous variable, take the reduced form for y2, (15.26), and plug it into the structural equation (15.22). This gives the reduced form for y1:
y1 = α0 + α1z1 + α2z2 + v1,
Find the α in terms of the B and the TT..
(ii) Find the reduced form error, v1, in terms of u1, v2, and the parameters.
(iii) How would you consistently estimate the aj?