Davis Stores sells clothing in 15 stores located around the southwestern United States. The managers at Davis are considering expanding by opening new stores and are interested in estimating costs in potential new locations. They believe that costs are driven in large part by store volume measured by revenue. The following data were collected from last years operations (revenues and costs in thousands of dollars).

Store	Revenues	Costs
101	$4,290	$4,499
102	2,417	3,274
103	6,023	5,466
104	4,362	4,473
105	3,199	4,246
106	4,403	3,984
107	7,084	5,314
108	2,064	3,324
109	6,366	5,448
110	3,798	3,529
111	4,266	4,654
112	5,165	3,580
113	3,742	3,126
114	5,577	5,035
115	3,074	3,271

Simple regression results from the data of Davis Stores are as follows.

Equation:
Store costs = $2,091.4 + (Revenue 48.4%)
Statistical data
Correlation coefficient	0.826
R2	0.682

Required:

a. Estimate store costs for a store with revenue of $4.4 million.

b. What percentage of the variation in store costs is explained by the independent variable?

Can you show me a break down, i cant understand this.