In: Statistics and Probability
. Suppose {et : t = −1, 0, 1, . . .} is a sequence of iid random variables with mean zero and variance 1. Define a stochastic process by xt = et − 0.5et−1 + 0.5et−2, t = 1, 2, . . .
a. Is xt stationary? Show your work.
b. Is xt weakly dependent? Again, show your work.
Plz help. maybe need use SAS to solve it