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 Total Shipping Month January Shipped Expense $ 2,000 $ 2,500 February March April May June July 645782 $ 1,900 $ 2,200 $ 2,500 $ 2,900 $ 1,400 2. Using the high-low method, estimate the cost formula for shipping expense. Variable shipping expense Fixed shipping expense per unit per month