Mac Renovations has been using the home's interior square feet as his cost driver in estimating costs.
It was brought to his attention that a home's external openings might be a better cost driver in estimating costs.
The following data was gathered from the last 12 houses he had painted.
House	Square Feet	Openings	Costs
1	2,500	7	$ 2,810
2	3,150	12	$ 3,742
3	2,800	8	$ 3,100
4	2,850	8	$ 3,150
5	4,750	16	$ 4,700
6	2,950	8	$ 3,225
7	2,700	7	$ 2,920
8	2,550	6	$ 2,836
9	2,600	7	$ 3,242
10	3,700	13	$ 4,112
11	2,650	7	$ 3,210
12	3,550	12	$ 3,965
Compute the scattergraph, the total cost equation, and the r-squared for
each cost driver in estimating costs.
Which cost driver is better and why?
(check figure: square feet variable costs = .86 and openings fixed costs = 1,750.76)