Rogen Corporation manufactures a single product. The standard cost per unit of product is shown below.

Direct materials3 pound plastic at $7.00 per pound		$ 21.00
Direct labor1.0 hours at $12.00 per hour		12.00
Variable manufacturing overhead		7.00
Fixed manufacturing overhead		7.00
Total standard cost per unit		$47.00

The predetermined manufacturing overhead rate is $14 per direct labor hour ($14.00 1.0). It was computed from a master manufacturing overhead budget based on normal production of 5,400 direct labor hours (5,400 units) for the month. The master budget showed total variable costs of $37,800 ($7.00 per hour) and total fixed overhead costs of $37,800 ($7.00 per hour). Actual costs for October in producing 4,500 units were as follows.

Direct materials (13,620 pounds)		$ 96,702
Direct labor (4,330 hours)		53,692
Variable overhead		46,620
Fixed overhead		18,380
Total manufacturing costs		$215,394

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. Compute the overhead controllable variance and the overhead volume variance.

what is overhead controllable variance?