Removing Seasonality from Sales Data

A catalog company is interested in modeling the upward trend of sales of its men's clothing line on a set of predictor variables (such as the number of catalogs mailed and the number of phone lines open for ordering). To this end, the company collected monthly sales of men's clothing for a 10-year period. This information is collected in catalog.sav. See the topic Sample Files for more information.

To perform a trend analysis, you must remove any seasonal variations present in the data. This task is easily accomplished with the Seasonal Decomposition procedure.

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