4. (15 pts) Regression: A company is investigating the relationship between its advertising expenditures and the sales of their products. The following data represents a sample of 10 products. Note that AD = Advertising dollars in K and S = Sales in thousands $. 1) (5 pts) Find the equation of the regression line, using Advertising dollars as the independent variable and Sales as the response variable. 2) (3 pts) Plot the scatter diagram and the regression line. 4) (5 pts) Find r2 and interpret it in the words of the problem. 5) (2 pts) Use the line to predict the Sales if Advertising dollars = $50 K