Simulate and plot the ACF, to lag 50, of the following time series:

(a).X1,X2,...,X500 is a white noise time series following a Normal distribution N(0,1).

(b).X1,X2,...,X500 is a AR(1) from Textbook Exercise 2.4 with=0.8.

(c).X1,X2,...,X500 is a random walk series from Textbook Exercise 2.5 with= 5 and2w= 1.

Assume the white noise series wt follows a Normal distribution.

Comment on the differences you see in the three ACF plots.