2. Consider a simple linear regression model Y 2530+,le +U. Suppose that we interpret this as a causal model. That is: we assume that the observable X and the unobservable U determine Y. Suppose that E(U|XJ = on + aux, where an and cu are mustants and m a U. (i) Obtain the conditional expectation function E(Y|X] {i.e., write E{Y|X] in terms of 0:9, 315.30,;31.' and X}. (ii) Let ha and b] solve the following minimization problem minE[(Y tn 11202]. tutu [s of equal to .31? Explain