1. Slide Presentation by Mark Karscig Central Missouri State University
Intermediate Microeconomics and Its Application 9th Edition by Walter Nicholson, Amherst College
Slide Presentation by
Mark Karscig
Central Missouri
State University
© 2004 Thomson Learning/South-Western

2. Chapter 1
Economic Models
© 2004 Thomson Learning/South-Western

3. What is Microeconomics?
The study of the allocation of scarce resources among alternative uses
Microeconomics
The study of the economic choices individuals and firms make and how those choices create markets

4. Economic Models
Simple theoretical descriptions that capture the essentials of how the economy works
Used because the “real world” is too complicated to describe in detail
Models tend to be “unrealistic” but useful
While they fail to show every detail (such as houses on a map) they provide enough structure to solve the problem (such as how a map provides you with a way to solve how to drive to a new location)

5. The Production Possibility Frontier
A graph showing all possible combinations of goods that can be produced with a fixed amount of resources
Figure 1.1 shows a production possibility frontier where the good goods are food and clothing produced per week
At point A, 10 units of food and 3 units of clothing can be produced

6. FIGURE 1.1: Production Possibility Frontier
Amount
of food
per week A 10 B 4
Amount
of clothing
per week 3 12

7. The Production Possibility Frontier
At point B, 4 units of food can be produced and 12 units of clothing
Without more resources, points outside the frontier are unattainable
This demonstrates a basic fact that resources are scarce

8. Opportunity Cost
The cost of a good or service as measured by the alternative uses that are foregone by producing the good or service

9. Opportunity Cost Example
As shown in Figure 1.1, if the economy produces one more unit of clothing beyond the 10 that it produces at point A, the amount of food produced decreases by 1/2 from 10 to 9.5
Thus, the opportunity cost of one unit of clothing is 1/2 unit of food at point A

10. FIGURE 1.1: Production Possibility Frontier
Amount
of food
per week
Opportunity cost of
clothing = ½ pound of food A 10
9.5
Amount
of clothing
per week 3 4

11. Opportunity Cost Example
Figure 1.1 also shows that the opportunity cost of clothing is much higher at point B (1 unit of clothing costs 2 units of food)
The increasing opportunity costs of producing even more clothing is consistent with Ricardo’s and Marshall’s ideas of increasing marginal cost

12. FIGURE 1.1: Production Possibility Frontier
Amount
of food
per week
Opportunity cost of
clothing = 2 pounds
of food B 4 2
Amount
of clothing
per week 12 13

13. FIGURE 1.1: Production Possibility Frontier
Amount
of food
per week
Opportunity cost of
clothing = ½ pound of food A 10
9.5
Opportunity cost of
clothing = 2 pounds
of food B 4 2
Amount
of clothing
per week 3 4 12 13

14. APPLICATION 1.1: Do Animals Understand Economics?
Nature provides examples of where animals have scarcity affect their choices
Birds of prey recognize a trade-off between spending time and energy in one area and moving to another location
To avoid using too much energy, animals will leave an area before the food supply is exhausted

15. Uses of Microeconomics
While the uses of microeconomics are varied, one useful way to categorize is by types of users
Individuals making decisions regarding jobs, purchases, and finances
Businesses making decisions regarding the demand for their product or their costs
Governments making policy decisions regarding laws and regulations

16. APPLICATION 1.2: Is It Worth Your Time to Be Here?
The typical U.S. college student pays about $18,000 per year in tuition, fees, and room and board charges. One might conclude then, that the “cost” of 4 years of college is about $72,000.
A number of studies have suggested that college graduates earn more than those without such an education.

17. APPLICATION 1.3: Saving Blockbuster
The largest video rental company incurred a huge financial loss primarily because of the high price of first-run movies
A large part of the “price” of the movie to the customer was not finding the movie in stock.
Blockbuster reached an agreement to guarantee availability and reverse its losses.

18. APPLICATION 1.4: Microsoft and Antitrust
The central issue of this case is whether or not Microsoft is illegally “monopolizing” various segments of the software industry in violation of the Sherman Antitrust Act.
MIT professor Franklin Fisher suggests that the real danger is allowing Microsoft to dominate the internet browser market which would eliminate competition.

19. APPLICATION 1.4: Microsoft and Antitrust
MIT professor Richard Schmalensee argues that Microsoft has not acted like a monopoly in the pricing of the Windows operating system
The judge’s decision will have to try to strike a balance between the operating system monopoly and the ability of Microsoft to be innovative

20. The Basic Supply-Demand Model
A model describing how a good’s price is determined by the behavior of the individual’s who buy the good and the firms that sell it.
Economists argue that market behavior can generally be explained by this model that captures the relationship between consumers’ preferences and firms’ costs.

21. Adam Smith and the Invisible Hand
Adam Smith ( ) saw prices as the force that directed resources into activities where they were most valuable
Prices told both consumers and firms the “worth” of the good.
Smith’s somewhat incomplete explanation for prices was that they were determined by the costs to produce the goods.

22. Adam Smith and the Invisible Hand
Since labor was the primary resource used, this led Smith to embrace a labor-based theory of prices.
If catching deer took twice as long as catching a beaver, one deer should trade for two beaver (the relative price of a deer is two beaver’s).
In Figure 1.1(a), the horizontal line at P* shows that any number of deer can be produced without affecting the relative cost

23. FIGURE 1.2(a): Smith’s Model
Price P*
Quantity per week

24. David Ricardo and Diminishing Returns
David Ricardo ( ) believed that labor and other costs would rise with the level of production
for example, as new less fertile land was cultivated, it would require more labor
This increasing cost argument is now referred to as the law of diminishing returns

25. David Ricardo and Diminishing Returns
The relative price of a good could be practically any amount, depending upon how much was produced
The level of production represented the quantity the country needed to survive
In Figure 1.2(b), as the needs of the country increase from Q1 to Q2 prices increase from P1 to P2

26. FIGURE 1.2(b): Ricardo’s Model
Price P1 Q1
Quantity per week

27. FIGURE 1.2(b): Ricardo’s Model
Price P2 P1 Q1 Q2
Quantity per week

28. FIGURE 1.2: Early Views of Price Determination
Quantity per week Q1 Q2
Quantity per week
(a) Smith model ’
(b) Ricardo model ’

29. Marginalism and Marshall’s Model of Supply and Demand
Ricardo’s model was unable to explain the fall in the relative prices of good during the nineteenth century so a more general model was needed
Economists argued the willingness of people to pay for a good will decline as they have more of it

30. Marginalism and Marshall’s Model of Supply and Demand
People will be willing to consume more of a good only if the price is lower
The focus of the model was on the value of the last, or marginal, unit purchased
Alfred Marshall ( ) showed how the forces of demand and supply simultaneously determined price

31. Marginalism and Marshall’s Model of Supply and Demand
In Figure 1.3, the amount of a good purchased per period is shown on the horizontal axis and the price of the good is shown on the vertical axis
The demand curve shows the amount people want to buy at each price and is negatively sloped reflecting the marginalism principle

32. Marginalism and Marshall’s Model of Supply and Demand
The upward sloping supply curve reflects the idea of increasing cost of making one more unit of a good as total production increases
Supply reflects increasing marginal costs and demand reflects decreasing marginal usefulness

33. FIGURE 1.3: The Marshall Supply-Demand Cross
Price
Supply
Demand
Quantity
per week

34. Market Equilibrium
In Figure 1.3, the demand and supply curve intersect at the market equilibrium point P*, Q*
P* is the equilibrium price: The price at which the quantity demanded by buyers of a good is equal to the quantity supplied by sellers of the good

35. FIGURE 1.3: The Marshall Supply-Demand Cross
Price
Demand
Supply . P*
Equilibrium point
Quantity
per week Q*

36. Market Equilibrium
Both demanders and suppliers are satisfied at this price, so there is no incentive for either to alter their behavior unless something else happens
Marshall compared the roles of supply and demand in establishing market equilibrium to the two blades of a pair of scissors working together in order to make a cut

37. Nonequilibrium Outcomes
If something causes the price to be set above P*, demanders would wish to buy less than Q* while suppliers would produce more than Q*
If something causes the price to be set below P*, demanders would wish to buy more than Q* while suppliers would produce less than Q*

38. Change in Market Equilibrium: Increased Demand
Figure 1.4 shows the case where people’s demand for the good increases as represented by the shift of the demand curve from D to D’
A new equilibrium is established where the equilibrium price has increased to P**

39. FIGURE 1.4: An increase in Demand Alters Equilibrium Price and Quantity
per week

40. FIGURE 1.4: An increase in Demand Alters Equilibrium Price and Quantity
per week

41. Change in Market Equilibrium: decrease in Supply
In Figure 1.5 the supply curve has shifted leftward reflecting a decrease in supply brought about because of an increase in supplier costs (say an increase in wages)
At the new equilibrium price P** consumers respond by reducing quantity demanded along the Demand curve D

42. FIGURE 1.5: A shift in Supply Alters Equilibrium Price and Quantity
Quantity
per week

43. FIGURE 1.5: A shift in Supply Alters Equilibrium Price and Quantity
Quantity
per week

44. How Economists Verify Theoretical Models
Two methods are used
Testing Assumptions: Verifying economic models by examining validity of the assumptions on which they are based
Testing Predictions: Verifying economic models by asking if they can accurately predict real-world events

45. Testing Assumptions
One approach would be to determine if the assumptions are reasonable
The obvious problem is that people have differing opinion regarding reasonable
Empirical evidence can also be used
Results of such methods have had problems similar to those found in opinion polls

46. Testing Predictions
Economists, such as Milton Friedman argue that all theories require unrealistic assumptions
The theory is only useful if it can be used to predict real-world events
Even if firms state they don’t maximize profits, if their behavior can be predicted by using this assumption, the theory is useful

47. Models of Many Markets
Marshall's model of supply and demand is a partial equilibrium model: An economic model of a single market
To show the effects of a change in one market on others requires a general equilibrium model: An economic model of a complete system of markets

48. APPLICATION 1.5: Economics According to Bono
The Spring 2002 trip to Africa by the Irish rock star Bono and U.S. Treasury Secretary Paul O’Neill sparked much interesting dialogue about economics
Bono claimed that recently enacted agricultural subsidies in the U.S. were harming struggling farmers in Africa

49. APPLICATION 1.5: Economics According to Bono
In Figure 1 U.S. farm subsidies reduce the world price of this crop from P* to P**.
Exports from this African country fall from QS – QD to Q’S – Q’D

50. Figure 1: U.S. Subsidies Reduce African ExportsQD
Q’D
Q’S QS Q

51. The Positive-Normative Distinction
Distinction between theories that seek to explain the world as it is and theories that postulate the way the world should be
To many economists, the correct role for theory is to explain the way the world is (positive) rather than the way it should be (normative)
Positive economics is the primary approach of the text

52. APPLICATION 1.6: Do Economists Ever Agree?
Many jokes and popular opinion suggest that economists do not agree on many issues
This belief arises primarily because people fail to distinguish between positive and normative issues
As Table 1 shows, there is much agreement regarding positive issues but much less agreement with normative issues

53. TABLE 1: Percentage of Economists Agreeing with Various Propositions in Three Nations