7. The method used to separate mixed costs that uses only two data points (even if more reliable points are available) is called: a. regression analysis b. scatter graphing c. the engineering approach d. the high-low method 8. After all costs have been covered by the firm's sales, the amount remaining is the called the a. variable; gross profit b. cost of goods sold; contribution margin c. variable; contribution margin d. fixed; gross margin 9. In the basic mathematical equation, the Y represents: a. total cost b. fixed cost c. unit variable cost d. activity level 10. The main difference between a contribution income statement and a functional income statement is that the functional income statement does not classify costs as: a. product and period b. product and mixed c. period and fixed d. fixed and variable