4.2 (Data le: Transact) The data in this example consists of a sample of branches of a large Australian bank (Cunningham and Heathcote, 1989). Each branch makes transactions of two types, and for each of the branches we have recorded the number t1 of type 1 transactions and the number t2 of type 2 transactions. The response is ti me,the total minutes of labor used by the branch. Dene a = (t1 + t2)l2 to be the average transaction time, and d = t1 t2, and t the following four mean functions M1: E(timeit 1, t2) = u, +ut 1 +21t2 M2: E(timeltl, t2) = ... +32a+42d M3: E(timelt 1, t2) = [3m + 23t2+ 43d M4: E(timelt1, t2) = (it... + l4tl+ Mt2+ya+ 544d 4.2.1 In the t of M4, some of the coefcients estimates are labeled as \"aliased\" or else they are simply omitted. Explain what this means and why this happens. 4.2.2 What aspects of the tted regressions are the same? What aspects are different? 4.2.3 Why is the estimate for 122 different in M1 and M3