The McGraw Company is accumulating data to be used in preparing its annual profit plan for the coming year. The cost behavior pattern of the maintenance costs must be determined. The accounting staff has suggested that linear regression be employed to derive an equation in the form of y= a + bx for maintenance costs. Data regarding the maintenance hours and costs for last year and the results of the regression analysis are as follows: (CMA adapted) January February March April May June July August September October November December Sum Average Hours of Activity 480 630 810 580 1,000 640 630 1,040 970 930 720 690 9,120 760 Maintenance Costs $ 4,540 3,340 3,940 3,160 4,690 3,300 3,370 4,810 4,600 4,390 3,640 3,500 $ 47,280 3,940 2,160.35 2.3416 A coefficient B coefficient Standard error of the a coefficient Standard error of the b coefficient Standard error of the estimate 601.114 0.77027 472.948 0.48030 Lanuaru ELLUL UL Lne v CUELLICIEN Standard error of the estimate R2 T-value a T-value b 472.948 0.48030 3.594 3.040 Vhat is the variable cost per hour using the high-low method to estimate the cost equation? $.57 $.48 $0.0085 $0.0072