Stefan Edberg Co. has the following standard costs: Standard Price Standard Quantity or Hours Standard Cost Per Unit or Rate Direct materials 7.0 ounces $ 4.00 per ounce $ 28.00 Direct labor 0.7 hours $ 14.00 per hour $ 9.80 Variable overhead 0.7 hours $ 9.00 per hour $ 6.30 The company reported the following results concerning this product in May. Actual output 2,900 units Raw materials used in production 21,000 ounces Purchases of raw materials 21,900 ounces Actual direct labor-hours 2.000 hours Actual cost of raw materials purchases $ 89.790 Actual direct labor cost $ 32.400 Actual variable overhead cost $ 3,200 Calculate the following variances: Materials price variance Materials quantity variance Labor rate variance Labor efficiency variance