Final answer:
When determining the quantity of a factor of production to use, a manager should refer to the cost function and factor payment costs, such as raw materials, rent, wages, interest, and profit.
Step-by-step explanation:
When a manager determines how much of a factor of production a firm should use, she should look at the firm's production function and the related factor payment costs. These costs include prices for raw materials, rent for land or buildings, wages and salaries for labor, interest and dividends for the use of financial capital, and profit for entrepreneurship. The cost function plays a critical role here as it is a mathematical expression that shows the cost of producing different levels of output. Understanding the cost function helps managers determine the most efficient combination of inputs to achieve the desired level of output while maintaining profitability.