2. Let {Wt}t in z ∼ WN(0, sigma ^2) and define the time series {Xt}t in z by Xt = Wt + 0.8Wt−2, t in z, with sigma ^2 = 1. Compute the mean and autocorrelation function of {Xt}t in Z. [Total 20 marks]
Added by Kristen R.
Step 1
Since {Wt}t in Z is a white noise process with mean 0, and Xt = Wt + 0.8Wt−2, we can compute the mean of Xt as follows: E[Xt] = E[Wt + 0.8Wt−2] = E[Wt] + 0.8E[Wt−2] Since Wt and Wt−2 are both white noise processes with mean 0, their expected values are also 0. Show more…
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