The sum of the direct labor mix variance and the direct labor yield variance equals the direct labor efficiency variance. The favorable mix variance arises from using more of the cheaper labor (and less of the costlier labor) than the budgeted mix. The yield variance indicates that the guitars required more total inputs (253 hours) than expected (250 hours) for the production of 25 guitars. Both variances are relatively small and probably within tolerable limits. It is likely that Earl, who is less experienced, worked more slowly than George, which caused the unfavorable yield variance. Trevor Joseph should be careful that using more of the cheaper labor does not reduce the quality of the guitar or how customers perceive it.