A marketing firm wishes to find a function that relates the sales S of a product and A, the amount spent on advertising the product. The data are obtained from past experience. Advertising and sales are measured in thousands of dollars.

Advertising Expenditures, A ……………..………………………….. Sales, S

20 ……………………………………………………………………………. 335

22 ……………………………………………………………………………. 335

22.5 …………………………………….……………………………………. 338

24 ……………………………………………………………………………. 343

24 …………………………………………………………………….………. 341

27 ………………………………………..………………………….………. 350

28.3 ……………………………………….…………………………………. 351

(a) Does the relation defined by the set of ordered pairs (A, S) represent a function?

(b) Draw a scatter diagram of the data.

(c) Using a graphing utility,find the line of best fit that models the relation between advertising expenditures and sales.

(d) Interpret the slope.

(e) Express the relationship found in part (c) using function notation.

(f) What is the domain of the function?

(g) Predict sales if advertising expenditures are $25,000.