1 The presence of a substance and the amount of that substance. 2  Thus, an assay may be done for example to determine the level of thyroid hormones in the blood of a person suspected of being hypothyroid (or hyperthyroid). 3  The biological or pharmacological potency of a drug. Thus, an assay may be done for example to determine the level of thyroid hormones in the blood of a person suspected of being hypothyroid (or hyperthyroid). 2  The biological or pharmacological potency of a drug. 3  For example, an assay may be done of a vaccine to determine its potency.
The total cost curve graphically represents the relation between total cost and the quantity of production. This curve can be derived in two ways. One is to plot a schedule of numbers relating output quantity and total cost. The other is to vertically add the total variable cost curve and the total fixed cost curve.he total cost curve is frequently used with a total revenue curve to determine the profit maximizing level of production for a firm. However, this curve is perhaps most important as the basis for deriving the average total cost curve and the marginal cost curve.
Minimum Average Total Cost For a U-shaped average total cost curve, average total cost is at its minimum level atthe bottom of the U. Economists call the quantity that corresponds to the minimum 9 CHAPTER 8 SECTION 2: TWO KEY CONCEPTS: MARGINAL COST AND AVERAGE COST.verage variable cost, or AVC, is variable cost divided by the quantity of out- 6 CHAPTER 8 SECTION 2: TWO KEY CONCEPTS: MARGINAL COST AND AVERAGE COSTA U-shaped average total costcurve falls at low levels of output,then rises at higher levels.