Define Average Total Cost and Average Variable Cost

Average Total Cost:   The amount spent on producing every unit of output. The average cost is calculated by dividing the total level of cost by the level of output. The average fixed cost will be made up of two elements; the average fixed and average variable cost. The average cost curve will tend to be u-shaped because of the presence of increasing and then diminishing returns.

Average Variable Cost:   The average variable cost is the total variable cost separated by output. The average variable cost curve will generally be u-shaped because of the presence of enhancing returns initially in the short run decreasing average variable costs initially. Eventually, though, diminishing returns will set in and the average variable cost will begin to rise.