Refer to the data in E3–3.

Data from E3-3

The following data relating to units shipped and total shipping expense have been assembled by Archer Company, a manufacturer of large, custom-built air-conditioning units for commercial buildings:

Required
1. Using the least-squares regression method, estimate a cost formula for shipping expense.
2. If you also completed E3–3, prepare a simple table comparing the variable and fixed-cost elements of shipping expense as computed under the high–low method, the scattergraph method and the least-squares regression method.

Month January February March April May June July Units shipping 36 4578 2 Total shipped expense 1,800 2,300 1,700 2,000 2,300 2,700 1,200