Ravena Labs., Inc. makes a single product which has the following standards: Direct materials: 2.5 ounces at $20 per ounce Direct labor: 1.4 hours at $12.50 per hour Variable manufacturing overhead: 1.4 hours at 3.50 per hour Variable manufacturing overhead is applied on the basis of standard direct labor-hours. The following data are available for October 3,750 units of compound were produced during the month. . There was no beginning direct materials inventory Direct materials purchased: 12,000 ounces for $225,000. The ending direct materials inventory was 2,000 ounces Direct labor-hours worked: 5,600 hours at a cost of $67,200 Variable manufacturing overhead costs incurred amounted to $18,200, Variable manufacturing overhead applied to products: $18,375 The variable overhead efficiency variance for October is