Required information [The following information applies to the questions displayed below) Phillips Company manufactures air-conditioning units for commercial buildings and has noticed considerable variation in shipping expenses from month to month as per the data below Units Shipped 4 4 5 Month January February March April May June July Total Shipping Expense $ 2,160 $ 3,060 $ 2,550 $1,264 $ 2,160 $ 2,910 $ 4,224 4. What is the cost formula for shipping expenses