Describe how total variable costs and unit variable costs behave with changes in the level of activity. Which of the following costs would be classified as variable and which would be classified as fixed, if units produced is the activity base? Direct materials costs Electricity costs of $0.35 per kilowatt-hour Describe how total fixed costs and unit fixed costs behave with changes in the level of activity. In applying the high-low method of cost estimation to mixed costs, how is the total fixed cost estimated? High-Low Method Obj. 1 The manufacturing costs of Rosenthal Industries for the first three months of the year follow: Using the high-low method, determine (a) the variable cost per unit and (b) the total fixed cost