Copyright © 2010 Pearson Addison-Wesley. All rights reserved. Chapter 3 Demand and Supply

Copyright © 2010 Pearson Addison-Wesley. All rights reserved.

Chapter 3

Demand and Supply


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Did You Know That...

• No new oil refineries have been built in the U.S. since 1976?

• Recently, however, Hyperion, a Dallas-based company, announced its intention to build a new refinery at Elk Pont, South Dakota.

• By using demand and supply you can develop a better understanding of why we sometimes see large increases in the price of gasoline.


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Did You Know That… (cont’d)

• Markets

– Arrangements that individuals have for exchanging with one another

– Represent the interaction of buyers and sellers for goods and services

– Markets set the prices we pay and receive.• Automobile market• Health care market• Labor market• Stock market


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Demand

• A schedule showing how much of a good or service people will purchase at any price during a specified time period, other things being constant

• Law of Demand

– Quantity demanded is inversely related to price, holding other factors constant.

• Price Qd

• Price Qd


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Figure 3-1 The Individual Demand Schedule and the Individual Demand Curve, Panel (b)


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Demand (cont’d)

• What are we holding constant?

– Income

– Tastes and preferences

– Price of other goods

– Many other factors

• Market Demand– The demand of all consumers in the

marketplace for a particular good or service


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Shifts in Demand

• Scenario

– Imagine the federal government gives every student registered in a college, university, or technical school in the United States a laptop with a slot for secure digital cards.

• If some factor other than price changes, we can show its effect by moving the entire demand curve, shifting the curve left or right.


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Figure 3-4 A Shift in the Demand Curve

Suppose the federal government gives every student a notebook computer

Suppose universities prohibit the use of notebook computers


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Shifts in Demand

• Factors that shift the demand curve

– Income (normal vs. inferior goods)

– Tastes and preferences

– The prices of related goods• Substitutes (a higher price of one good leads to a higher

demand of another good)

• Complements (a higher price of one good leads to a lower demand of another good)

– Expectations of income, future prices etc.


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Changes in demand versus changes in quantity demanded

A change in the price changes the quantity of a good demanded= movement along the curve

Change in demand = Shifting the demand curve


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The Law of Supply

• Supply

– The amount of a product or service that firms are willing to sell at alternative prices

• Law of Supply

– The price of a product or service and the quantity supplied are directly related.

• P Qs

• P Qs


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Figure 3-8 The Market Supply Schedule and the Market Supply Curve for Secure Digital Cards, Panel (b)


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Shifts in Supply

• Scenario

– A new method of manufacturing SD cards significantly reduces the cost of production.

– What will producers of SD cards do?


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Figure 3-9 A Shift in the Supply Curve

If some other factor than price changes, the only way we can show its effect is by moving the entire supply curve

If costs decrease, supply increases

If costs increase, supply decreases


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Shifts in Supply (cont'd)

• Determinants of supply

– Cost of inputs

– Technology and productivity (same as lower cost)

– Taxes and subsidies

– Price expectations

– Number of firms in industry


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The Determinants of SupplyCost of Inputs

S1

Q/Units

Decrease in cost increases supply

S2Increase in costdecreases supply

S3

Price


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The Determinants of SupplyTechnology and Productivity

S1

Q/Units

Improvements in technology or increases in productivity increase supply

S2Decreases in productivity decrease supply

S3

Price


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• Changes in supply versus changes in quantity supplied

– A change in one or more of the non-price determinants will lead to a change in supply.

• This is a shift of the whole curve.


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Changes in supply versus changes in quantity supplied

A change in a good’s own price leads to a change in quantity supplied. This is a movement along the same curve.

Factors other than its own price shift the supply curve


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Putting Demand and Supply Together

• Putting demand and supply together

• Equilibrium (Market Clearing) Price– The price that clears the market

– The price at which quantity demanded equals quantity supplied

– The price where the demand curve intersects the supply curve


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Figure 3-10 Putting Demand and Supply Together, Panel (b)


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Putting Demandand Supply Together (cont'd)

• Shortages

– The situation when quantity demanded is greater than quantity supplied

• Qd > Qs

– Exist at any price below the equilibrium price

• Surpluses

– The situation when quantity supplied is greater than quantity demanded

• Qd < Qs

– Exist at any price above the equilibrium price


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Policy Example: Should Shortages in the Ticket Market Be Solved by Scalpers?

• If you’ve ever tried to get tickets to the big game you know all about “shortages.”

• Since the quantity of tickets is fixed, the price can go pretty high.

• Enter the scalper.


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Myth #3: Businesses charge whatever they want to.

• Is life unfair?• The answer to most questions with a freely

determined market price is: Supply and demand

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Copyright © 2010 Pearson Addison-Wesley. All rights reserved. Chapter 3 Demand and Supply