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:

Month	Units Shipped	Total Shipping Expense
January	2	$	1,400
February	5	$	1,900
March	3	$	1,300
April	4	$	1,600
May	6	$	1,900
June	7	$	2,900
July	1	$	800

Exercise 5A-4 Part 2

2. Using the high-low method, estimate the cost formula for shipping expense.