Ortman Corporation makes a product with the following standard costs: Standard Quantity or Hours Standard Price or Rate Direct materials 7.2 liters $7.00 per liter Direct labor 1.6 hours $22.00 per hour Variable overhead 1.6 hours $1.00 per hour The company reported the following results concerning this product in May: Actual output 2,200 units Raw materials used in production 15,620 liters Actual direct labor-hours 3,425 hours Purchases of raw materials 17,360 liters Actual price of raw materials purchased $ 7.40 per liter Actual direct labor rate $21.50 per hour Actual variable overhead rate $0.80 per hour The company applies variable overhead on the basis of direct labor-hours. The direct materials purchases variance is computed when the materials are purchased. The materials quantity variance for May is: $1,555 F $1,555 U $1,540 U $1,540 F