Lacourse Incorporated's inspection costs are listed below: Inspection Units Produced Costs January 420 $ 6,110 February 370 $ 5,629 March 439 $ 6,325 April 454 $ 6,463 May 396 $ 5,879 June 371 $ 5,632 July 446 $ 6,390 August 397 $ 5,892 Management believes that inspection cost is a mixed cost that depends on units produced. Using the least-squares regression method, the estimate of the fixed component of inspection cost per month is closest to