A bicycle company wants to measure the effectiveness of different types of advertising media in the promotion of its new bicycle. Specifically, the company is interested in the effectiveness of radio advertising and newspaper advertising. A sample of 22 cities with approximately equal populations is selected for study during a test period of one month. Each city is allocated a specific expenditure level both for radio advertising and for newspaper advertising. The sales of the bicycle (in thousands of dollars) and also the levels of media expenditure (in thousands of dollars) during the test month are recorded.
State the multiple regression equation.