The number of blood tests performed and the related costs over the last nine months in Brentline Hospital are given below Month January February March April May June July August September Blood Tests Blood Performed Test Costs 5,215 $67,499 7,100 $88,989 4,770 $61,488 4,120 $53,446 $55,339 3,300 $44,140 3,790 $49,428 5,045 $64,665 4,955 $64,181 4,215 Required: 1. Using the high-low method, estimate the cost formula for blood tests, (Round cost per unit answer to 2 decimal places.)