Weekly sales (in hundreds) of Pert shampoo at the SaveMor drug chain for the past 16 weeks are as follows: Management wishes to forecast the annual demand for Pert shampoo in order to determine an...

Weekly sales (in hundreds) of Pert shampoo at the SaveMor drug chain for the past 16 weeks are as follows:

Management wishes to forecast the annual demand for Pert shampoo in order to determine an optimal order policy.

a. Graph this time series.

b. Verify statistically that a stationary model is appropriate for forecasting this time series.

c. Using a four-period moving average, forecast the annual demand for Pert shampoo. (Assume sales = demand.)