Electric Dreams Corporation is a wholesaler of a large variety of light fittings and other lighting

needs. The company's accountant, Henry Benry, has recently completed a cost study of the

firm's shipping department in which he used the weight of supplies loaded or unloaded at the

company's loading dock to quantify the department$$s activity. Henry compiled the following

data.

Month

Supplies loaded

or unloaded $($kg$)$

Shipping

department costs

January $5,400$ $$70,200$

February $4,80067,800$

March $3,90067,500$

April $3,00061,200$

May $6,60066,600$

June $7,20075,300$

July $6,00072,000$

August $5,40068,400$

September $7,80072,720$

October $3,30066,300$

November $3,60068,100$

December $4,20068,100$

Required:

a$.$ Estimate the shipping department's cost behaviour using the high low method. Use an

equation to express the results of this estimation method.

b$.$ Predict the shipping department$$s cost for a month when loads totalling $4,500$ kilograms

are moved.