Exercise 6-18 Swifty Industries is a leading manufacturer of golf balls. Each golf ball requires 1 minute of direct labor time to complete. Swifty used 7,440 direct labor hours in July to produce 439,800 golf balls. Swifty's standard labor rate is $15 per direct labor hour, and the actual labor rate in July was $13.09. Calculate Swifty's direct labor efficiency variance for July. (If variance is zero, select "Not Applicable" and enter o for the amounts.) Direct labor efficiency variance $