Engberg Company installs lawn sod in home yards. The companys most recent monthly contribution format income statement follows:$$ Required:$1.$ What is the companys degree of operating leverage?$2.$ Using the degree of operating leverage, estimate the impact on net operating income of a $6\%$ increase in unit sales$\mathrm{.}3.$ Construct a new contribution format income statement for the company assuming a $6\%$ increase in unit sales.