=+3-21 K Estimating a cost function, high-low method OBJECTIVES 1, 4 Pierre’s Restaurant wants to find an equation to estimate monthly utility costs. Pierre’s Restaurant has been in business for one year and has collected the following cost data for utilities:

Month Electricity bill Kilowatthours used Telephone bill Telephone minutes used Water bill Litres of water used January $360 1 200 $92.00 1 100 $60 30 560 February $420 1 400 $91.20 1 060 $60 26 800 March $549 1 830 $94.80 1 240 $60 31 450 April $405 1 350 $89.60 980 $60 29 965 May $588 1 960 $98.00 1 400 $60 30 568 June $624 2 080 $98.80 1 440 $60 25 540 July $522 1 740 $93.40 1 170 $60 32 690 August $597 1 990 $96.20 1 310 $60 31 222 September $630 2 100 $95.60 1 280 $60 33 540 October $615 2 050 $93.80 1 190 $60 31 970 November $594 1 980 $91.00 1 050 $60 28 600 December $633 2 110 $97.00 1 350 $60 34 100 Required 1 Which of the above costs is variable? Fixed? Mixed? Explain.