F I L E Consider the following sample data, consisting of 10 observations. The data are also on th e text website, labeled Exercise 18.1.

t 1 2 3 4 5 6 7 8 9 10 yt 11 12 9 12 10 8 11 12 10 9

a. Construct a 3-period moving average and plot it along with the actual series. Comment on smoothing.

b. Use the 3-period moving average to make forecasts and compute the resulting MSE and MAD.

c. Make a forecast for period 11.