True or false

13. A fixed cost is a cost that remains constant, in total, regardless of changes in the level of activity. 14. Manufacturing overhead usually includes various fixed costs such as depreciation, insurance, property taxes, rent, and supervisory salaries. 15. Cost behavior refers to how a cost reacts to changes in the level of activity. 16. A variable cost varies, in total, in direct proportion to changes in the level of activity. 17. Assume that a company paid $50,000 several years ago for a special-purpose machine. The machine was used to make a product that is now obsolete and is no longer being sold. The $50,000 should be considered in decision making