A CPA firm estimates that an audit will require the following work: Type of Auditor Expected Hours Cost per Hour Standard Costs Manager 10 $50 $ 500 Senior 20 40 800 Staff 40 30 1,200 Totals 70 $2,500 The actual hours and costs were: Type of Auditor Actual Hours Actual Cost per Hour Actual Costs Manager 9 $52 $ 468 Senior 22 38 836 Staff 44 30 1,320 Totals 75 $2,624 Required: Calculate the direct labor, wage rate, and labor efficiency variances for each type of auditor and interpret.