Bargain Rental Car offers rental cars in an off-airport location near a major tourist destination in California. Management would like to better understand the behavior of the company's costs. One of those costs is the cost of washing cars. The company operates its own car wash facility in which each rental car that is returned is thoroughly cleaned before being released for rental to another customer. Management believes that the costs of operating the car wash should be related to the number of rental returns. Accordingly, the following data have been compiled: Month Returns Costs 2,380 10,825 2,421 S 11,865 2,586 S 11,332 2,725 $ 12,422 2,968 13,850 3,281 14,419 3,353 S 14,935 3,489 $ 15,738 3,057 S 13,563 2,876 $ 11,889 2,735 12,683 2,983 $ 13,796 January February March May June July August September October November December