Required:

$1.$ What was the master budget variance for July? Was this variance favorable or unfavorable?

$2.$ Compute the July sales volume variance and the flexible$-$budget variance for the month, both in terms of contribution margin and in terms of operating income.

$4.$ Prepare pro$-$forma budgets for activities within its relevant range of operations. Prepare a flexible budget for each of the following two output levels:

$3,900$ units.

$4,300$ units.