Ch03_Parkin_Econ_Lecture_3_2024 (1).ppt

3 DEMAND AND SUPPLY  After studying this chapter, you will be able to:  Describe a competitive market and think about a price as an opportunity cost  Explain the influences on demand  Explain the influences on supply  Explain how demand and supply determ...

3 DEMAND AND SUPPLY  After studying this chapter, you will be able to:  Describe a competitive market and think about a price as an opportunity cost  Explain the influences on demand  Explain the influences on supply  Explain how demand and supply determine prices and quantities bought and sold  Use the demand and supply model to make predictions about changes in prices and quantities © 2014 Pearson Education  In 2015.16, the prices of meat and other food stuff in Namibia rose rapidly. Why do some prices rise? And why do some prices fall, and some fluctuate? This chapter answers these questions. The demand and supply model that you’re about to study is the main tool of economics. It explains how prices are determined and how they guide the use of resources to influence What, How, and For Whom goods and services are produced. © 2014 Pearson Education  Markets and Prices A market is any arrangement that enables buyers and sellers to get information and do business with each other. A competitive market is a market that has many buyers and many sellers so no single buyer or seller can influence the price. The money price of a good is the amount of money needed to buy it. The relative price of a good—the ratio of its money price to the money price of the next best alternative good—is its opportunity cost. © 2014 Pearson Education  Demand If you demand something, then you 1. Want it, 2. Can afford it, and 3. Have made a definite plan to buy it. Wants are the unlimited desires or wishes people have for goods and services. Demand reflects a decision about which wants to satisfy. The quantity demanded of a good or service is the amount that consumers plan to buy during a particular time period, and at a particular price. © 2014 Pearson Education  Demand The Law of Demand The law of demand states: Other things remaining the same, the higher the price of a good, the smaller is the quantity demanded; and … the lower the price of a good, the larger is the quantity demanded. Why does a change in the price change the quantity demanded? Two reasons:  Substitution effect  Income effect © 2014 Pearson Education  Demand Substitution Effect When the relative price (opportunity cost) of a good or service rises, people seek substitutes for it, so the quantity demanded of the good or service decreases. Income Effect When the price of a good or service rises relative to income, people cannot afford all the things they previously bought, so the quantity demanded of the good or service decreases. © 2014 Pearson Education  Demand Demand Curve and Demand Schedule The term demand refers to the entire relationship between the price of the good and quantity demanded of the good. A demand curve shows the relationship between the quantity demanded of a good and its price when all other influences on consumers’ planned purchases remain the same. © 2014 Pearson Education  Demand Figure 3.1 shows a demand curve for energy bars. © 2014 Pearson Education  Demand A rise in the price, other things remaining the same, brings a decrease in the quantity demanded and a movement up along the demand curve. A fall in the price, other things remaining the same, brings an increase in the quantity demanded and a movement down along the demand curve. © 2014 Pearson Education  Demand Willingness and Ability to Pay A demand curve is also a willingness-and-ability-to- pay curve. The smaller the quantity available, the higher is the price that someone is willing to pay for another unit. Willingness to pay measures marginal benefit. © 2014 Pearson Education  Demand A Change in Demand When some influence on buying plans other than the price of the good changes, there is a change in demand for that good. The quantity of the good that people plan to buy changes at each and every price, so there is a new demand curve. When demand increases, the demand curve shifts rightward. When demand decreases, the demand curve shifts leftward. © 2014 Pearson Education  Demand Six main factors that change demand are  The prices of related goods  Expected future prices  Income  Expected future income and credit  Population  Preferences © 2014 Pearson Education  Demand Prices of Related Goods A substitute is a good that can be used in place of another good. A complement is a good that is used in conjunction with another good. When the price of a substitute for an energy bar rises or when the price of a complement of an energy bar falls, the demand for energy bars increases. © 2014 Pearson Education  Demand Expected Future Prices If the price of a good is expected to rise in the future, current demand for the good increases and the demand curve shifts rightward. Income When income increases, consumers buy more of most goods and the demand curve shifts rightward. A normal good is one for which demand increases as income increases (clothing). An inferior good is a good for which demand decreases as income increases. © 2014 Pearson Education  Demand Expected Future Income and Credit When income is expected to increase in the future or when credit is easy to obtain, the demand might increase now. Population The larger the population, the greater is the demand for all goods. Preferences People with the same income have different demands if they have different preferences. © 2014 Pearson Education  Demand Figure 3.2 shows an increase in demand. Because an energy bar is a normal good, an increase in income increases the demand for energy bars. © 2014 Pearson Education  Demand A Change in the Quantity Demanded Versus a Change in Demand Figure 3.3 illustrates the distinction between a change in demand and a change in the quantity demanded. © 2014 Pearson Education  Demand A Movement along the Demand Curve When the price of the good changes and other things remain the same, the quantity demanded changes and there is a movement along the demand curve. © 2014 Pearson Education  Demand A Shift of the Demand Curve If the price remains the same but one of the other influences on buyers’ plans changes, demand changes and the demand curve shifts. © 2014 Pearson Education  Supply If a firm supplies a good or service, then the firm 1. Has the resources and the technology to produce it, 2. Can profit from producing it, and 3. Has made a definite plan to produce and sell it. Resources and technology determine what it is possible to produce. Supply reflects a decision about which technologically feasible items to produce. The quantity supplied of a good or service is the amount that producers plan to sell during a given time period at a particular price. © 2014 Pearson Education  Supply The Law of Supply The law of supply states: Other things remaining the same, the higher the price of a good, the greater is the quantity supplied; and the lower the price of a good, the smaller is the quantity supplied. The law of supply results from the general tendency for the marginal cost of producing a good or service to increase as the quantity produced increases (Chapter 2, page 35). Producers are willing to supply a good only if they can at least cover their marginal cost of production. © 2014 Pearson Education  Supply Supply Curve and Supply Schedule The term supply refers to the entire relationship between the quantity supplied and the price of a good. The supply curve shows the relationship between the quantity supplied of a good and its price when all other influences on producers’ planned sales remain the same. © 2014 Pearson Education  Supply Figure 3.4 shows a supply curve of energy bars. A rise in the price, other things remaining the same, brings an increase in the quantity supplied. © 2014 Pearson Education  Supply Minimum Supply Price A supply curve is also a minimum-supply-price curve. As the quantity produced increases, marginal cost increases. The lowest price at which someone is willing to sell an additional unit rises. This lowest price is marginal cost. © 2014 Pearson Education  Supply A Change in Supply When some influence on selling plans other than the price of the good changes, there is a change in supply of that good. The quantity of the good that producers plan to sell changes at each and every price, so there is a new supply curve. When supply increases, the supply curve shifts rightward. When supply decreases, the supply curve shifts leftward. © 2014 Pearson Education  Supply The six main factors that change supply of a good are:  The prices of factors of production  The prices of related goods produced  Expected future prices  The number of suppliers  Technology  State of nature © 2014 Pearson Education  Supply Prices of Factors of Production If the price of a factor of production used to produce a good rises, the minimum price that a supplier is willing to accept for producing each quantity of that good rises. So a rise in the price of a factor of production decreases supply and shifts the supply curve leftward. © 2014 Pearson Education  Supply Prices of Related Goods Produced A substitute in production for a good is another good that can be produced using the same resources. The supply of a good increases if the price of a substitute in production falls. Goods are complements in production if they must be produced together. The supply of a good increases if the price of a complement in production rises. © 2014 Pearson Education  Supply Expected Future Prices If the price of a good is expected to rise in the future, supply of the good today decreases and the supply curve shifts leftward. The Number of Suppliers The larger the number of suppliers of a good, the greater is the supply of the good. An increase in the number of suppliers shifts the supply curve rightward. © 2014 Pearson Education  Supply Technology Advances in technology create new products and lower the cost of producing existing products. So advances in technology increase supply and shift the supply curve rightward. The State of Nature The state of nature includes all the natural forces that influence production—for example, the weather. A natural disaster decreases supply and shifts the supply curve leftward. © 2014 Pearson Education  Supply Figure 3.5 shows an increase in supply. An advance in the technology increases the supply of energy bars and shifts the supply curve rightward. © 2014 Pearson Education  Supply A Change in the Quantity Supplied Versus a Change in Supply Figure 3.6 illustrates the distinction between a change in supply and a change in the quantity supplied. © 2014 Pearson Education  Supply A Movement Along the Supply Curve When the price of the good changes and other influences on sellers’ plans remain the same, the quantity supplied changes and there is a movement along the supply curve. © 2014 Pearson Education  Supply A Shift of the Supply Curve If the price remains the same but some other influence on sellers’ plans changes, supply changes and the supply curve shifts. © 2014 Pearson Education  Market Equilibrium Equilibrium is a situation in which opposing forces balance each other. Equilibrium in a market occurs when the price balances the plans of buyers and sellers. The equilibrium price is the price at which the quantity demanded equals the quantity supplied. The equilibrium quantity is the quantity bought and sold at the equilibrium price.  Price regulates buying and selling plans.  Price adjusts when plans don’t match. © 2014 Pearson Education  Market Equilibrium Figure 3.7 illustrates the market equilibrium—the price at which quantity demanded equals quantity supplied. 13 15 © 2014 Pearson Education  Market Equilibrium Price as a Regulator There is a surplus of 6 million energy bars. 13 15 If the price is $2.00 a bar, the quantity supplied exceeds the quantity demanded. A surplus of 6 million bars. © 2014 Pearson Education  Market Equilibrium There is a surplus of 6 million energy bars. 13 15 If the price is $1.00 a bar, the quantity demanded exceeds the quantity supplied. A shortage of 9 million bars. © 2014 Pearson Education  Market Equilibrium There is a surplus of 6 million energy bars. 13 15 If the price is $1.50 a bar, the quantity supplied equals the quantity demanded. No shortage or surplus of bars. © 2014 Pearson Education  Market Equilibrium Price Adjustments At prices above the equilibrium price, a surplus forces the price down. At prices below the equilibrium price, a shortage forces the price up. At the equilibrium price, buyers’ plans and sellers’ plans agree and the price doesn’t change until some event changes either demand or supply. © 2014 Pearson Education  Predicting Changes in Price and Quantity An Increase in Demand Figure 3.8 shows that when demand increases the demand curve shifts rightward. At the original price, there is now a shortage. The price rises, and the quantity supplied increases along the supply curve. © 2014 Pearson Education  Predicting Changes in Price and Quantity An Increase in Supply Figure 3.9 shows that when supply increases the supply curve shifts rightward. At the original price, there is now a surplus. The price falls, and the quantity demanded increases along the demand curve. © 2014 Pearson Education  Predicting Changes in Price and Quantity All Possible Changes in Demand and Supply A change in demand or supply or both demand and supply changes the equilibrium price and the equilibrium quantity. © 2014 Pearson Education  Predicting Changes in Price and Quantity Change in Demand with No Change in Supply When demand increases, equilibrium price rises and the equilibrium quantity increases. © 2014 Pearson Education  Predicting Changes in Price and Quantity When demand decreases, the equilibrium price falls and the equilibrium quantity decreases. © 2014 Pearson Education  Predicting Changes in Price and Quantity Change in Supply with No Change in Demand When supply increases, the equilibrium price falls and the equilibrium quantity increases. © 2014 Pearson Education  Predicting Changes in Price and Quantity When supply decreases, the equilibrium price rises and the equilibrium quantity decreases. © 2014 Pearson Education  Predicting Changes in Price and Quantity Increase in Both Demand and Supply An increase in demand and an increase in supply increase the equilibrium quantity. The change in equilibrium price is uncertain because the increase in demand raises the equilibrium price and the increase in supply lowers it. © 2014 Pearson Education  Predicting Changes in Price and Quantity Decrease in Both Demand and Supply A decrease in both demand and supply decreases the equilibrium quantity. The change in equilibrium price is uncertain because the decrease in demand lowers the equilibrium price and the decrease in supply raises it. © 2014 Pearson Education  Predicting Changes in Price and Quantity Decrease in Demand and Increase in Supply A decrease in demand and an increase in supply lowers the equilibrium price. The change in equilibrium quantity is uncertain because the decrease in demand decreases the equilibrium quantity and the increase in supply increases it. © 2014 Pearson Education  Predicting Changes in Price and Quantity Increase in Demand and Decrease in Supply An increase in demand and a decrease in supply raises the equilibrium price. The change in equilibrium quantity is uncertain because the increase in demand increases the equilibrium quantity and the decrease in supply decreases it. © 2014 Pearson Education