Wolverine Company's average cost per unit is $$1\mathrm{.}425$ at the $16,000-$unit level of activity and $$1\mathrm{.}38$ at the $20,000-$unit level of activity. The selling price is $$3\mathrm{.}00$ per unit. Assume that all of the activity levels mentioned in this problem are within the relevant range. Predict the following items for Wolverine Company: Required: $1.$ Variable cost per unit. $2.$ Total fixed cost per period. $3.$ Total expected costs at the $18,000-$unit level of activity. $4.$ Total Contribution Margin at the $18,000$ unit level of production and sales.