Longview Hospital performs blood tests in its laboratory. The following standards have
been set for each blood test performed:
During May, the laboratory performed 1,500 blood tests. On May 1 there were no direct
materials (plates) on hand; after a plate is used for a blood test it is discarded. Variable
overhead is assigned to blood tests on the basis of standard direct labor-hours. The
following events occurred during May:
• 3,600 plates were purchased for $9,540
• 3,200 plates were used for blood tests
• 340 actual direct labor-hours were worked at a cost of $5,550
The direct materials purchases variance is computed when the materials are purchased.
The variable overhead efficiency variance for May is: