In: Statistics and Probability
2. Let {Zt , t = 0, ±1, ±2, ...} be a sequence of independent random variables, each with mean EZt = 0 and variance Var(Zt) = σ 2 . Define Xt = ZtZt−1 + Zt−2.
• Compute the mean and the covariance function for Xt .
• Is {Xt} weakly stationary? Explain why.