Judith Thompson runs a florist shop on the Gulf Coast of Texas, specializing in floral arrangements for weddings and other special events. She advertises weekly in the local newspapers and is considering increasing her advertising budget. Before doing so, she decides to evaluate the past effectiveness of these ads. Five weeks are sampled, and the advertising in dollars and sales volume for each of these is shown in the following table.

Sales (1,000)

Advertising (100)

11

5

6

3

10

7

6

2

12

8

a. Develop a regression model that would help Judith evaluate her

advertising.

b. How reliable is the model?