please explain causes of variances

P3-3. Variable factory overhead variances. Coyote Corporation has provided the following data for August: Budgeted variable overhead cost ver machine-hour: Instructions: 2. Compute the variable overhead rate variances and efficiency variances for lubricants. a. Indicate whether each of the variances is favorable (F) or unfavorable (U). b. Explain possible causes of the variances. 3. Compute the variable overhead rate variances and efficiency variances for supplies. a. Indicate whether each of the variances is favorable (F) or unfavorable (U). b. Explain possible causes of the variances