E3.28 LO 3.9 Estimating cost behaviour using multiple methods: retailer Quik Chek, a chain of convenience stores, has store hours that fluctuate from month to month as the tourist trade varies. The electricity costs and hours of operation for the past six months for one of the company's stores follow: Month Total hours of operation Total electricity cost January 700 $5700 February 600 5100 March April 550 4860 500 4800 May 400 3900 June 450 4050 Required 1. Use the high-low method to estimate the cost behaviour of the store's electricity costs, assuming that the variable costs vary in proportion to the hours of operation. Express the cost behaviour in formula form (Y= a + bx). What is the variable electricity cost per hour of operation? 2. Use regression analysis to estimate the cost behaviour of the store's electricity costs. Express the cost behaviour in equation form. What is the variable electricity cost per hour of operation? 3. During July, the store will be open 420 hours. Predict the store's total electricity cost for July using each of the cost estimation methods employed in requirements 1 and 2.