Exercise 7.9.8. For an AR(2) process, use the YuleWalker equations, with y() replacing y() to obtain estimates

Exercise 7.9.8. For an AR(2) process, use the Yule–Walker equations, with σˆy(·)

replacing σy(·) to obtain estimates

φˆ1 =

ρˆ (1) (1−ρˆ (1))

1−ρˆ (1)2 and

φˆ2 =

ρˆ (2)−ρˆ (1)2 1−ρˆ (1)2 .