Adriana Corporation manufactures football equipment. In planning for next year, the managers want to understand the relation between activity and overhead costs. Discussions with the plant supervisor suggest that overhead seems to vary with labor hours, machine-hours, or both. The following data were collected from last year's operations. Page 208 Month Labor-Hours Machine-Hours Overhead Costs 3,625 6.775 $513,435 3,575 7,035 518,960 3,400 7,600 549,575 3,700 7,265 541,400 3,900 7,955 581,145 3,775 7,895 572,320 3,700 6,950 535,110 3,625 510,470 3,550 7,270 532,195 3,975 7725 565,335 3,375 6,490 503.775 3,550 8,020 564,210 6,530 Required a. Use the high-low method to estimate the fixed and variable portions of overhead costs based on machine-hours. b. Managers expect the plant to operate at a monthly average of 7.500 machine hours next year. What are the estimated monthly overhead costs, assuming no inflation