• Consider the AR seasonal model, xt=xt-12+wt+wt-12, where <1, <1, andw0, w1, w2,...~N0,w are i.i.d.Show that the process is stationary with the auto-variance and auto-covariance functions are given by

1+21-2w2

auto-covariance={covxt,xt-12h=h covxt,xt-12h+1=1+2h

h=1, 2, 3, ... covariance=0 otherwise