​Mike's Service Station performs oil changes for cars. Each oil change has a standard time of 0.4 direct labor hours. The standard direct labor hour rate is $ 19.00 per hour. Data relating to oil changes for the month of September​ follow: Actual number of oil changes performed 2 comma 400 Actual direct labor hours worked 900 Actual total direct labor cost $ 4 comma 500 What is the labor rate variance for​ September?