The following labor standards have been established for a particular product: standard labor hours per unit of output standard labor rate 8.5 hours $18.10 per hour The following data pertain to operations concerning the product for the last month: actual hours worked 4,300 hours actual total labor cost $78,475 actual output 500 units Calculate the labor rate variance (LRV): $637.50 UNFAVORABLE (U) $645 FAVORABLE (F) $645 UNFAVORABLE (U) $637.50 FAVORABLE (F)