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		715			1,363		$	102,669
2		715			1,401			103,772
3		680			1,516			109,890
4		740			1,457			108,218
5		785			1,589			116,271
6		765			1,570			114,562
7		750			1,384			107,023
8		715			1,309			102,068
9		705			1,456			106,413
10		805			1,547			113,078
11		675			1,294			97,987
12		710			1,610			109,995

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 1,600 machine-hours next year. What are the estimated monthly overhead costs, assuming no inflation?