The following labor standards have been established for a particular product: Standard labor hours per unit of output Standard labor rate 3 hours $12 per hour The following data pertain to operations concerning the product for the last month: Actual hours worked Actual total labor cost Actual output 6,700 hours $ 80, 200 2,200 units Required: a. What is the labor rate variance for the month? b. What is the labor efficiency variance for the month