1. Copyright © 2004 South-Western 4 The Market Forces of Supply and Demand

2. Copyright © 2004 South-Western DEMAND Quantity demanded is the amount of a good that buyers are willing and able to purchase. Law of Demand The law of demand states that, other things equal, the quantity demanded of a good falls when the price of the good rises.

3. Copyright © 2004 South-Western Catherine’s Demand Schedule

4. Figure 1 Catherine’s Demand Schedule and Demand Curve Copyright © 2004 South-Western Price of Ice-Cream Cone 0 2.50 2.00 1.50 1.00 0.50 1234567891011 Quantity of Ice-Cream Cones $3.00 12 1. A decrease in price... 2....increases quantity of cones demanded.

5. Copyright © 2004 South-Western Market Demand versus Individual Demand Market demand refers to the sum of all individual demands for a particular good or service. Graphically, individual demand curves are summed horizontally to obtain the market demand curve.

6. Copyright © 2004 South-Western Shifts in the Demand Curve Change in Quantity Demanded Movement along the demand curve. Caused by a change in the price of the product.

7. Copyright © 2004 South-Western 0 D Price of Ice- Cream Cones Quantity of Ice-Cream Cones A tax that raises the price of ice-cream cones results in a movement along the demand curve. A B 8 1.00 $2.00 4 Changes in Quantity Demanded

8. Copyright © 2004 South-Western Shifts in the Demand Curve Consumer income Prices of related goods Tastes Expectations Number of buyers

9. Copyright © 2004 South-Western Shifts in the Demand Curve Change in Demand A shift in the demand curve, either to the left or right. Caused by any change that alters the quantity demanded at every price.

10. Figure 3 Shifts in the Demand Curve Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone Quantity of Ice-Cream Cones Increase in demand Decrease in demand Demand curve,D 3 Demand curve,D 1 Demand curve,D 2 0

11. Table 1 Variables That Influence Buyers Copyright©2004 South-Western

12. SUPPLY Quantity supplied is the amount of a good that sellers are willing and able to sell. Law of Supply The law of supply states that, other things equal, the quantity supplied of a good rises when the price of the good rises.

13. Copyright © 2004 South-Western Ben’s Supply Schedule

14. Figure 5 Ben’s Supply Schedule and Supply Curve Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone 0 2.50 2.00 1.50 1.00 1234567891011 Quantity of Ice-Cream Cones $3.00 12 0.50 1. An increase in price... 2.... increases quantity of cones supplied.

15. Copyright © 2004 South-Western Market Supply versus Individual Supply Market supply refers to the sum of all individual supplies for all sellers of a particular good or service. Graphically, individual supply curves are summed horizontally to obtain the market supply curve.

16. Copyright © 2004 South-Western Shifts in the Supply Curve Input prices Technology Expectations Number of sellers

17. Copyright © 2004 South-Western Shifts in the Supply Curve Change in Quantity Supplied Movement along the supply curve. Caused by a change in anything that alters the quantity supplied at each price.

18. Copyright © 2004 South-Western 1 5 Price of Ice- Cream Cone Quantity of Ice-Cream Cones 0 S 1.00 A C $3.00 A rise in the price of ice cream cones results in a movement along the supply curve. Change in Quantity Supplied

19. Copyright © 2004 South-Western Shifts in the Supply Curve Change in Supply A shift in the supply curve, either to the left or right. Caused by a change in a determinant other than price.

20. Figure 7 Shifts in the Supply Curve Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone Quantity of Ice-Cream Cones 0 Increase in supply Decrease in supply Supply curve,S 3 curve, Supply S 1 curve,S 2

21. Table 2 Variables That Influence Sellers Copyright©2004 South-Western

22. SUPPLY AND DEMAND TOGETHER Equilibrium Price The price that balances quantity supplied and quantity demanded. On a graph, it is the price at which the supply and demand curves intersect. Equilibrium Quantity The quantity supplied and the quantity demanded at the equilibrium price. On a graph it is the quantity at which the supply and demand curves intersect.

23. Copyright © 2004 South-Western At $2.00, the quantity demanded is equal to the quantity supplied! SUPPLY AND DEMAND TOGETHER Demand ScheduleSupply Schedule

24. Figure 8 The Equilibrium of Supply and Demand Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone 0123456789101112 Quantity of Ice-Cream Cones 13 Equilibrium quantity Equilibrium price Equilibrium Supply Demand $2.00

25. Figure 9 Markets Not in Equilibrium Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone 0 Supply Demand (a) Excess Supply Quantity demanded Quantity supplied Surplus Quantity of Ice-Cream Cones 4 $2.50 10 2.00 7

26. Figure 9 Markets Not in Equilibrium Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone 0 Quantity of Ice-Cream Cones Supply Demand (b) Excess Demand Quantity supplied Quantity demanded 1.50 10 $2.00 7 4 Shortage

27. Copyright © 2004 South-Western Three Steps to Analyzing Changes in Equilibrium Decide whether the event shifts the supply or demand curve (or both). Decide whether the curve(s) shift(s) to the left or to the right. Use the supply-and-demand diagram to see how the shift affects equilibrium price and quantity.

28. Figure 10 How an Increase in Demand Affects the Equilibrium Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone 0 Quantity of Ice-Cream Cones Supply Initial equilibrium D D 3....and a higher quantity sold. 2.... resulting in a higher price... 1. Hot weather increases the demand for ice cream... 2.00 7 New equilibrium $2.50 10

29. Figure 11 How a Decrease in Supply Affects the Equilibrium Copyright©2003 Southwestern/Thomson Learning Price of Ice-Cream Cone 0 Quantity of Ice-Cream Cones Demand New equilibrium Initial equilibrium S1S1 S2S2 2.... resulting in a higher price of ice cream... 1. An increase in the price of sugar reduces the supply of ice cream... 3....and a lower quantity sold. 2.00 7 $2.50 4

30. Table 4 What Happens to Price and Quantity When Supply or Demand Shifts? Copyright©2004 South-Western