Supply and Demand

In today’s lesson we will consider: •The basic supply concept •The basic demand concept •Equilibrium market prices •How the above affects business organisations Copyright © 2004 South-Western 2 SUPPLY AND DEMAND I: HOW MARKETS WORK The Market Forces of Supply and Demand 4 Copyright © 2004 South-Western • Supply and demand are the two words that economists use most often. • Supply and demand are the forces that make market economies work. • Modern economics is about supply, demand, and market equilibrium. Copyright © 2004 South-Western MARKETS AND COMPETITION • A market is a group of buyers and sellers of a particular good or service. • The terms supply and demand refer to the behaviour of people . . . as they interact with one another in markets. Copyright © 2004 South-Western MARKETS AND COMPETITION • Buyers determine demand. • Sellers determine supply Copyright © 2004 South-Western Competitive Markets • A competitive market is a market in which there are many buyers and sellers so that each has little impact on the market price. • For the purpose of these exercises, it will be assumed there is perfect competition. Copyright © 2004 South-Western Competition: Perfect and Otherwise • Perfect Competition • Products are the same • Numerous buyers and sellers so that each has no influence over price • Monopoly • One seller, and seller controls price 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. Copyright © 2004 South-Western The Demand Curve: The Relationship between Price and Quantity Demanded • Demand Schedule • The demand schedule is a table that shows the relationship between the price of the good and the quantity demanded. Copyright © 2004 South-Western Catherine’s Demand Schedule Copyright © 2004 South-Western The Demand Curve: The Relationship between Price and Quantity Demanded • Demand Curve • The demand curve is a graph of the relationship between the price of a good and the quantity demanded. • EXERCISE – using Catherine’s demand schedule, put draw a demand curve for Catherine’s ice cream. • Does it follow the ‘law of demand’? Copyright © 2004 South-Western Figure 1 Catherine’s Demand Schedule and Demand Curve Price of Ice-Cream Cone $3.00 2.50 1. A decrease in price ... 2.00 1.50 1.00 0.50 0 1 2 3 4 5 6 7 8 9 10 11 12 Quantity of Ice-Cream Cones 2. ... increases quantity of cones demanded. 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. Copyright © 2004 South-Western Movement in the Demand Curve • Change in Quantity Demanded • Movement along the demand curve. • Caused by a change in the price of the product. Copyright © 2004 South-Western Changes in Quantity Demanded Price of IceCream Cones $2.00 B A tax that raises the price of ice-cream cones results in a movement along the demand curve. A 1.00 D 0 4 8 Quantity of Ice-Cream Cones Copyright © 2004 South-Western Shifts in the Demand Curve – due to factors other than Price The demand curve for ice cream shows how much ice cream people buy at any given price. However, there are many other factors beyond price that influence customers’ buying decisions. • Consumer income • Prices of related goods (eg frozen yoghurt) • Tastes (changing due to health reasons) • Expectations (about the future may affect Your demand today eg if your income is going To increase next month, you may be willing to buy more • Number of buyers (if buyers increase, demand curve would shift to the right. 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 other than price changes. Copyright © 2004 South-Western Figure 3 Shifts in the Demand Curve Price of Ice-Cream Cone Increase in demand Decrease in demand Demand curve, D2 Demand curve, D1 Demand curve, D3 0 Quantity of Ice-Cream Cones Copyright©2003 Southwestern/Thomson Learning Table 1 Variables That Influence Buyers Copyright©2004 South-Western 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. (When the price of ice cream is high, selling ice cream is profitable, so the quantity supplied is large). When the price of ice cream falls, the quantity supplied falls as well. Copyright © 2004 South-Western The Supply Curve: The Relationship between Price and Quantity Supplied • Supply Schedule • The supply schedule is a table that shows the relationship between the price of the good and the quantity supplied. Copyright © 2004 South-Western Ben’s Supply Schedule Copyright © 2004 South-Western The Supply Curve: The Relationship between Price and Quantity Supplied • Supply Curve • The supply curve is the graph of the relationship between the price of a good and the quantity supplied. • EXERCISE – Draw a supply curve for Ben who supplies ice cream (on the same graph as Catherine’s demand curve) • Does the law of supply apply? Copyright © 2004 South-Western Figure 5 Ben’s Supply Schedule and Supply Curve Price of Ice-Cream Cone $3.00 1. An increase in price ... 2.50 2.00 1.50 1.00 0.50 0 1 2 3 4 5 6 7 8 9 10 11 12 Quantity of Ice-Cream Cones Copyright©2003 Southwestern/Thomson Learning 2. ... increases quantity of cones supplied. 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. Copyright © 2004 South-Western Shifts in the Supply Curve (caused by factors other than Price) What influences producers’ decisions about how much to sell? • • • • Input prices (raw ingredient prices) Technology (mechanisation) Expectations (for the future)? Number of sellers 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. Copyright © 2004 South-Western Change in Quantity Supplied Price of IceCream Cone S C A rise in the price of ice cream cones results in a movement along the supply curve. $3.00 1.00 A 0 1 5 Quantity of Ice-Cream Cones 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. Copyright © 2004 South-Western Figure 7 Shifts in the Supply Curve Price of Ice-Cream Cone Supply curve, S3 Supply curve, S1 Decrease in supply Supply curve, S2 Increase in supply 0 Quantity of Ice-Cream Cones Copyright©2003 Southwestern/Thomson Learning Table 2 Variables That Influence Sellers Copyright©2004 South-Western SUPPLY AND DEMAND TOGETHER • Equilibrium refers to a situation in which the price has reached the level where quantity supplied equals quantity demanded. Copyright © 2004 South-Western 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 meet. • 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 meet. Copyright © 2004 South-Western SUPPLY AND DEMAND TOGETHER Demand Schedule Supply Schedule At $2.00, the quantity demanded is equal to the quantity supplied! Copyright © 2004 South-Western Figure 8 The Equilibrium of Supply and Demand Price of Ice-Cream Cone Supply Equilibrium price $2.00 Equilibrium Equilibrium quantity 0 1 2 3 4 5 6 7 8 Demand 9 10 11 12 13 Quantity of Ice-Cream Cones Copyright©2003 Southwestern/Thomson Learning Equilibrium • Law of supply and demand • The claim that the price of any good adjusts to bring the quantity supplied and the quantity demanded for that good into balance. Copyright © 2004 South-Western Figure 10 How an Increase in Demand Affects the Equilibrium Price of Ice-Cream Cone 1. Hot weather increases the demand for ice cream . . . Supply $2.50 New equilibrium 2.00 2. . . . resulting in a higher price . . . Initial equilibrium D D 0 3. . . . and a higher quantity sold. 7 10 Quantity of Ice-Cream Cones Copyright©2003 Southwestern/Thomson Learning Three Steps to Analyzing Changes in Equilibrium • Shifts in Curves versus Movements along Curves • A shift in the supply curve is called a change in supply. • A movement along a fixed supply curve is called a change in quantity supplied. • A shift in the demand curve is called a change in demand. • A movement along a fixed demand curve is called a change in quantity demanded. Copyright © 2004 South-Western Figure 11 How a Decrease in Supply Affects the Equilibrium Price of Ice-Cream Cone S2 1. An increase in the price of sugar reduces the supply of ice cream. . . S1 $2.50 New equilibrium Initial equilibrium 2.00 2. . . . resulting in a higher price of ice cream . . . Demand 0 4 7 3. . . . and a lower quantity sold. Quantity of Ice-Cream Cones Copyright©2003 Southwestern/Thomson Learning Table 4 What Happens to Price and Quantity When Supply or Demand Shifts? Copyright©2004 South-Western Summary • Economists use the model of supply and demand to analyze competitive markets. • In a competitive market, there are many buyers and sellers, each of whom has little or no influence on the market price. Copyright © 2004 South-Western Summary • The demand curve shows how the quantity of a good depends upon the price. • According to the law of demand, as the price of a good falls, the quantity demanded rises. Therefore, the demand curve slopes downward. • In addition to price, other determinants of how much consumers want to buy include income, the prices of complements and substitutes, tastes, expectations, and the number of buyers. • If one of these factors changes, the demand curve shifts. Copyright © 2004 South-Western Summary • The supply curve shows how the quantity of a good supplied depends upon the price. • According to the law of supply, as the price of a good rises, the quantity supplied rises. Therefore, the supply curve slopes upward. • In addition to price, other determinants of how much producers want to sell include input prices, technology, expectations, and the number of sellers. • If one of these factors changes, the supply curve shifts. Copyright © 2004 South-Western Summary • Market equilibrium is determined by the intersection of the supply and demand curves. • At the equilibrium price, the quantity demanded equals the quantity supplied. • The behavior of buyers and sellers naturally drives markets toward their equilibrium. Copyright © 2004 South-Western Summary • To analyze how any event influences a market, we use the supply-and-demand diagram to examine how the even affects the equilibrium price and quantity. • In market economies, prices are the signals that guide economic decisions and thereby allocate resources. Copyright © 2004 South-Western