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.

Month	Labor-Hours			Machine-Hours			Overhead Costs
1		720			1,363		$	102,628
2		725			1,411			103,854
3		690			1,513			109,827
4		730			1,454			108,265
5		780			1,586			116,190
6		750			1,586			114,506
7		750			1,382			106,906
8		730			1,315			102,027
9		700			1,461			106,392
10		790			1,546			113,193
11		675			1,288			99,311
12		705			1,608			111,951

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 1,400 machine-hours next year. What are the estimated monthly overhead costs, assuming no inflation?