Olivet Devices sells two models of fitness devices. The budgeted price per unit for the wireless model is $57 and the budgeted price per unit for the wireless and cellular model is $102. The master budget called for sales of 55,200 wireless models and 13,800 wireless and cellular models during the current year. Actual results showed sales of 40,500 wireless models, with a price of $54 per unit, and 17,700 wireless and cellular models, with a price of $99 per unit. The standard variable cost per unit is $44 for a wireless model and $79 for a wireless and cellular model. Required: a. Compute the sales activity variance for these data. b. Break down the sales activity variance into mix and quantity parts