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 year's operations (revenues and costs in thousands of dollars): Store 101 102 103 Revenues $4,300 2,427 6,038 4,382 3,214 4,423 7,094 2,079 6,416 3,828 4,286 5,190 3,752 5,617 3,124 Costs $4,514 3,294 5,481 4,498 4,276 4,019 5,329 3,374 5,488 3,559 4,679 3,600 3,156 5,055 3,286 Simple regression results from the data of Davis Stores are as follows: Equation: Store costs = $2,121.4 + (Revenue x 48.0%) Statistical data Correlation coefficient 0.823 0.678 R2 Required: a. Estimate store costs for a store with revenue of $4.5 million. (Enter the answer in thousands of dollars. Round your answer to 2 decimal places.) Store cost b. What percentage of the variation in store costs is explained by the independent variable? (Enter answer as a percentage rounded to 1 decimal place.) Percentage of variation in store cost