Models of past cost behaviour are called cost functions. Factors that influence costs are called cost drivers (Horngren, Datar, and Rajan, Cost Accounting, 2018). Assume the cost data shown below are from a rug manufacturer. Indirect manufacturing labour costs consist of machine maintenance costs and setup labour costs. Machine-hours and direct manufacturing labour-hours are cost drivers.~ Indirect Direct Week Manufacturing Machine-Hours Manufacturing Labour Costs Labor-Hours $1,190 68