Sheridan Company applies overhead based on direct labour hours. Two direct labour hours are required for each unit of product. Planned production for the period was set at 8,500 units. Manufacturing overhead is budgeted at $136,000 for the period 120% of this cost is fixed). The 16,200 hours worked during the period resulted in the production of 8,000 units. The variable manufacturing overhead cost incurred was $1q,500 and the fixed manufacturing overhead cost was $28,000. Calculate the variable overhead eficiency (quantity) variance for the period