The following labor standards have been established for a particular product:Standard labor-hours per unit of output ............. 8.0 hours; Standard labor rate .............................................. $13.10 per hour; The following data pertain to operations concerning the product for the last month: Actual hours worked ............ 4,000 hours; Actual total labor cost ........... $53,000; Actual output ........................ 400 units. What is the labor efficiency variance for the month?