Question

6.  Industries whose firms have downward-sloping LRAC curves that reach the minimum efficient scale at large values of output relative to the size of the market:

            a.  Tend to have a large number of small firms.

            b.  Tend to have a small  number of large firms.

            c.  Tend to have a wide range of firm sizes.

            d.  Tend to have a few large firms and a few small ones.

7.  The Average/Marginal Rule says that

            a.  When MC is above ATC, ATC must be falling.

            b.  When MC is falling, ATC must be falling.

            c.  When MC is below AFC, AFC must be rising.

            d.  None of the above.

8.  The perfect substitutes model in production has:

            a.  Conventional isoquants

            b.  Linear isoquants.

            c.  L- shaped isoquants.

            d.  Backward-bending isoquants.

9.  The main point of Frank’s Cullen Gates story is:

            a.  Gates should move his miniature golf course to Manhattan.

            b.  Accounting and economic profits are the same.

            c.  Firm decisions should be made on the basis of economic profits.

            d.  Firm decisions should be made on the basis of accounting profits.

10.   The main point of Frank’s “An Efficient Manager” story is:

            a.  Efficient managers lower costs for their firms.

            b.  Firms with efficient managers will have lower costs in the long run.

            c.  Efficient managers will be paid more.

            d.  In the long run, firms with and without efficient managers will earn the same profits.

Answer 1

Once a firm has determined the least costly production technology, it can consider the optimal scale of production, or quantity of output to produce. Many industries experience economies of scale. Economies of scale refers to the situation where, as the quantity of output goes up, the cost per unit goes down. This is the idea behind “warehouse stores” like Costco or Walmart. In everyday language: a larger factory can produce at a lower average cost than a smaller factory. Figure illustrates the idea of economies of scale, showing the average cost of producing an alarm clock falling as the quantity of output rises. For a small-sized factory like S, with an output level of 1,000, the average cost of production is $12 per alarm clock. For a medium-sized factory like M, with an output level of 2,000, the average cost of production falls to $8 per alarm clock. For a large factory like L, with an output of 5,000, the average cost of production declines still further to $4 per alarm clock.

The average cost curve in Figure may appear similar to the average cost curves presented earlier in this module, although it is downward-sloping rather than U-shaped. But there is one major difference. The economies of scale curve is a long-run average cost curve, because it allows all factors of production to change. The short-run average cost curves presented earlier in this module assumed the existence of fixed costs, and only variable costs were allowed to change. One prominent example of economies of scale occurs in the chemical industry. Chemical plants have a lot of pipes. The cost of the materials for producing a pipe is related to the circumference of the pipe and its length. However, the volume of chemicals that can flow through a pipe is determined by the cross-section area of the pipe. The calculations in Table show that a pipe which uses twice as much material to make (as shown by the circumference of the pipe doubling) can actually carry four times the volume of chemicals because the cross-section area of the pipe rises by a factor of four (as shown in the Area column).

  Table Comparing Pipes: Economies of Scale in the Chemical Industry

	Circumference (2πr)	Area (πr2)
4-inch pipe	12.5 inches	12.5 square inches
8-inch pipe	25.1 inches	50.2 square inches
16-inch pipe	50.2 inches	201.1 square inches

A doubling of the cost of producing the pipe allows the chemical firm to process four times as much material. This pattern is a major reason for economies of scale in chemical production, which uses a large quantity of pipes. Of course, economies of scale in a chemical plant are more complex than this simple calculation suggests. But the chemical engineers who design these plants have long used what they call the “six-tenths rule,” a rule of thumb which holds that increasing the quantity produced in a chemical plant by a certain percentage will increase total cost by only six-tenths as much.