In preparing the annual profit plan for the coming year, wilkens company wants to determine the cost behavior pattern of the maintenance costs. wilkens has decided to use linear regression by employing the equation y = a + bx for maintenance costs. the prior year's data regarding maintenance hours and costs, and the results of the regression analysis are given here. hours maintenance of activity costs sum 4,480 $43,200 average 400 3,600 average cost per hour = $9.00; a = 684.65; b = 7.2884; standard error of a = 49.515; standard error of b = .12126; standard error of the estimate = 34.469; r2 = .99724. based upon the data derived from the regression analysis, 420 maintenance hours in a month would mean the maintenance costs (rounded to the nearest dollar) would be budgeted at: