average fixed cost -fixed costs divided by the quantity of output   average total cost -total cost divided by the quantity of output   average variable cost -variable costs divided by the quantity of output   constant returns to scale -the property whereby long-run average total cost stays the same as the quantity of output changes   diminishing marginal product -the property whereby the marginal product of an input declines as the quantity of the input increases   diseconomies of scale -the property whereby long-run average total cost rises as the quantity of output increases   economies of scale -the property whereby long-run average total cost falls as the quantity of output increases   efficient scale -the quantity of output that minimizes average total cost   fixed costs -costs that do not vary with the quantity of output produced   marginal cost -the increase in total cost that arises from an extra unit of production   marginal product -the increase in output that arises from ana additional unit of input   production function -the relationship between quantity of inputs used to make a good and the quantity of output of that good   profit -total revenue minus total cost   total cost -the amount a firm pays to buy the inputs into production   total revenue -the amount a firm receives for the sale of its output   variable costs -costs that do vary with the quantity of output produced