Cold Products Corporation manufactured 27,000 ice chests during September. The variable overhead cost-allocation base is $11.75 per machine-hour. The following variable overhead data pertain to September: Actual BudgetedProduction 27,000 units 26,000 unitsMachine-hours 13,500 hours 7,800 hoursVariable overhead cost per machine-hour: $11.25 $11.75 What is the variable overhead efficiency variance