Inspection costs at one of Ratulowski Corporation’s factories are listed below:

Units Inspection
Produced Cost
April 777 $10,176
May 807 $10,404
June 798 $10,355
July 835 $10,665
August 822 $10,542
September 795 $10,313
October 805 $10,409
November 853 $10,795
December 796 $10,310

Management believes that inspection cost is a mixed cost that depends on units produced.
Using the high low method, create a cost formula for inspection cost. Round variable cost per unit (b) to two decimal places.