The business problem faced by consumer product companies is measuring the effectiveness of various types of advertising media in promoting their products. In particular, companies are interested in the effectiveness of radio advertising and newspaper advertising (including the cost of discount coupons). During the one-month testing period, data were collected from a sample of 22 cities with roughly the same population. Each city is allocated a specific expenditure level for radio advertising and newspaper advertising. Product sales (in $ '000) as well as media expenditure rates (in $' 000) during the test month were recorded, with results shown in

the following table:

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