... (2. 4 .25 )Population regression 510 10 20 3000 .2 0.40.60.81impulse response0 1 2 310010110 2 spectrum−15 −10 −5 0 5 10 15 2. 2 2. 4 2. 6 2. 833 .2 covariogram 20 40 60 80−3 2. 5 2 −1.5−1−0.500.5sample ... mt+1+logmt +2 )=vart(log mt+1)+vart(log mt +2 )+2covt(log mt+1, log mt +2 ) (2. 7.14)where covtis a conditional covariance. It can then be established that σ 2 1>σ 2 2 2 can occur ... control, chapter 5. 26 25 See Hamilton (1994) or Hansen and Sargent (in press). 26 See Hansen (19 82) , Eichenbaum (1991), Christiano and Eichenbaum (19 92) ,Burnside, Eichenbaum, and Rebelo (1993), and...