C The purchasing department buys the quantities of raw materials that are expected to be used in production each month. Raw materials inventories, therefore, can be ignored. Rogen Corporation manufactures a single product. The standard cost per unit of product is shown below. The predetermined manufacturing overhead rate is $10 per direct labor hour ($16.001.6). It was computed from a master manufacturing overhead budget based on normal production of 8,000 direct labor hours (5,000 units) for the month. The master budget showed total variable costs of $60,000 ( $7.50 per hour) and total fixed overhead costs of $20,000 ( $2.50 per hour). Actual costs for October in producing 4,800 units were as follows. (b) Compute the total overhead variance. Total overhead variance $