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A major source of revenue in Texas is a state sales tax on certain types of goods and services. Dcompiled and the state comptroller uses them to project future revenues for the state budget. Onparticular category of goods is classified as Retail Trade. Four years of quarterly data (in $millioone particular area of southeast Texas follow:(a) Compute seasonal indices for each quarter based on a CMA.(b) Deseasonalize the data and develop a trend line on the deseasonalized data.(c) Use the trend line to forecast the sales for each quarter of year 5.(d) Use the seasonal indices to adjust the forecasts found in part (c) to obtain the final forecasts.
Data are ne ons) for .
ForecastingMultiplicative decomposition4 seasonsDataPeriodDemandTime (x)AverageQuarter 12181Quarter 22472Quarter 32433250250.875Quarter 42924251.75252.625Quarter 52255253.5255Quarter 62546256.5257.375Quarter 72557258.25259.375Quarter 82998260.5261.875Quarter 92349263.25264.375Quarter 1026510265.5269Quarter 1126411272.5274.5Quarter 1232712276.5278.75Quarter 1325013281284.125Quarter 1428314287.25290.875Quarter 1528915294.5Quarter 1635616Average(a)RatiosSeason 1Season 2Season 3Season 40.9686098655 1.155863430.88235294120.98688683830.98313253011.141766110.8851063830.98513011150.9617486339 1.173094170.87989441270.9729265148Average0.88245124560.98164782150.97116367651.1569079(c, d)ForecastsPeriodUnadjustedSeasonalAdjusted17 300.0661991790.8824512456264.79379123Enter past demands in the data area. Do not change the time period nuEnter past demands in the data area. Do not change the time period nu