7. Sales Experience and Performance. A sales manager collected the following data on annual sales for new customer accounts and the number of years of experience for a sample of 10 salespersons.

Years of Annual Sales Salesperson Experience ($1000s)
1 1 80 2 3 97 3 4 92 4 4 102 5 6 103 6 8 111 7 10 119 8 10 123 9 11 117 10 13 136

a. Develop a scatter diagram for these data with years of experience as the independent variable.

b. Develop an estimated regression equation that can be used to predict annual sales given the years of experience.

c. Use the estimated regression equation to predict annual sales for a salesperson with 9 years of experience.