Federated Cooperatives Limited (FCL) is the largest wholesaler of grocery, hardware, and agricultural supplies in Western Canada, and operates warehouses in Saskatoon, Edmonton, Calgary, and Winnipeg. In the Calgary warehouse, a particular golf club is carried in stock. The demand for this golf club during each month of the period 2003-05 is listed below (note that FCL uses weekly time buckets, but for simplicity we have combined these into monthly data):

a. Determine the monthly relatives using the 12-period centred moving average method.
b. Deseasonalize the data, fit an appropriate model to the deseasonalized data, project it 12 months ahead, and reseasonaiize the projections to forecast monthly sales for 2006. (These forecasts will be used to plan purchases of the golf club from the manufacturer.)