! Required information [The following information applies to the questions displayed below.] Archer Company is a wholesaler of custom-built air-conditioning units for commercial buildings. It gathered the following monthly data relating to units shipped and total shipping expense: Units Shipped 4 7 5 Month January February March April May June July Total Shipping Expense $ 1,200 $ 1,700 $ 1,100 $ 1,400 $ 1,700 $ 2,700 $ 6 8 9 2 600 2. Using the high-low method, estimate the cost formula for shipping expense. per unit Variable shipping expense Fixed shipping expense per month