Assignment : Time series

Year	January	February	March	April	May	June	July	August	September	October	November	December
1996	4964	4968	5601	5454	5721	5690	5804	6040	5843	6087	6469	7002
1997	5416	5393	5907	5768	6107	6016	6131	6499	6249	6472	6946	7615
1998	5876	5818	6342	6143	6442	6407	6545	6758	6485	6805	7361	8079
1999	6061	6187	6792	6587	6918	6920	7030	7491	7305	7571	8013	8727
2000	6776	6847	7531	7333	7685	7518	7672	7992	7645	7923	8297	8537
2001	7005	6855	7420	7183	7554	7475	7687	7922	7426	7736	8483	9329
2002	7120	7124	7817	7538	7921	7757	7816	8208	7828

The Sales data from 1996 to 2002 is presented to you. The data seems to have trend and seasonality. For this reason, a time series decomposition approach is adopted to analyze the sales variable. Cyclic component is neglected and a additive model Yt = Tt + St+ It is adopted Develop the following a) Trend Line equation b) Seasonal Index for all months Jan to Dec c) Calculated all errors MAPE, MAD, MSE d) Develop Seasonally Adjusted Monthly Sales e) Forecast Seasonally Adjusted Monthly sales for first 9 months of 2002 f) How accurate are these compared to actual sales data in 2002? g) Forecast Sales in Oct 2002 h) Show the Actual Data and Forecast data in a graph; Show seasonally adjusted data and trend line together in a separate graph