Classifying Cost Behavior Classify the total costs of each of the following as variable, fixed, mixed, or step. Sales volume is the cost driver. (a) Salary of the department manager Answer (b) Memory chips in a computer assembly plant Answer (c) Real estate taxes Answer (d) Salaries of quality inspectors when each inspector can evaluate a Answer maximum of 1,000 units per day (e) Wages paid to production employees for the time spent working on products Answer (f) Electric power in a factory Answer (g) Raw materials used in production Answer (h) Automobiles rented on the basis of a fixed charge per day plus an Answer additional charge per mile driven (i) Sales commissions Answer (j) Straight-line depreciation