JJudy runs a flower shop on the Gulf Coast of Texas, specializing in floral arrangement for weddings and other special events. She advertises weekly in the local newspaper 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 dollars and sales volume for each of these is shown below.

Sales ($1,000)	Advertising ($100)
11	5
6	3
10	7
6	2
12	8

a. Develop a regression equation that would help Judy evaluate her advertising effectiveness. Find the coefficient of determination (r²) for this model.

b. Explain what your equation suggests in terms of the estimated sales increase for every unit increase in advertising and what the r² , you derived, explains concerning the relationship of two variables.