The following data are for a small firm:

Revenue Advertising Expenditures 88,000 80,000 84,000 92,000 96,000 104,000 108,000 116,000 118,000 120,000 20,000 18,000 22,000 24,000 22,000 24,000 26,000 26,000 28,000 30,000

(a) Use the regression method to show how spending on advertisement affects the firm’s revenue.

(b) Draw the estimated regression line to illustrate the errors, the slope, and the intercept.

(c) Estimate the firm’s revenue if the expenditure on advertisement becomes $45,000.