Armer Company is accumulating data to use 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 the use of linear regression to derive an equation for maintenance hours and costs. Data regarding the maintenance hours and costs for the last year and the results of the regression analysis follow:

MonthMaintenance CostMachine HoursJan.$4,200480Feb.3,000320Mar.3,600400Apr.2,820300May4,350500June2,960310July3,030320Aug.4,470520Sept.4,260490Oct.4,050470Nov.3,300350Dec.3,160340Sum$43,2004,800Average$3,600$400Average cost per hour$9.00a (intercept)$684.65b (coefficient)7.2884Standard error of the estimate34.469R-squared0.99724t-value for b60.105

The coefficient of determination for Armer's regression equation for the maintenance activities is