Superior Coop uses a standard cost system to account for the costs of its one product. Variable overhead is applied using direct labor hours. Standards allowed for each unit are 3.0 hours of labor at a variable overhead rate of $11. During November, Superior Coop produced 2,250 units. Payroll totaled $97,730 for 7,140 hours worked. Variable overhead incurred totaled $80,390
Calculate
a.Variable overhead rate variance (U or F or none)
b. Variable overhead efficiency variance (U or F or none)