An assay is an investigative (analytic) procedure in laboratory medicine, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence or amount or the functional activity of a target entity (the analyte). Qualitative assay, i.e. assays which generally give just a pass or fail, or positive or negative or some such sort of only small number of qualitative gradation rather than an exact quantity.
The average fixed cost (AFC) curve will decline as additional units are produced, and continue to decline. The average total cost (ATC) curve initially will decline as fixed costs are spread over a larger number of units, but will go up as marginal costs increase due to the law of diminishing returns.
The Relationship between total cost ,total fixed cost,total variable cost are as follows-. 2) Only total variable cost changes to total cost because total fixed cost always remains fixed and never increase and decrease with the change in level of output. 1) Average cost is the sum total of average fixed cost and average variable cost. AC=AFC+AVC. 2) The gap between AC and AVC comes closer and closer but never intersect each other because AC=AFC+AVC and AFC is continuously falling and never rises.