Principles of Microeconomics PDF

N. Gregory Mankiw Principles of Microeconomics Sixth Edition 4 The Market Forces of Supply and Demand...

N. Gregory Mankiw Principles of Microeconomics Sixth Edition 4 The Market Forces of Supply and Demand Premium PowerPoint Slides by © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Ron  In this chapter, look for the answers to these questions: What factors affect buyers’ demand for goods? What factors affect sellers’ supply of goods? How do supply and demand determine the price of a good and the quantity sold? How do changes in the factors that affect demand or supply affect the market price and quantity of a good? How do markets allocate resources? © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 2 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Markets and Competition  A market is a group of buyers and sellers of a particular product.  A competitive market is one with many buyers and sellers, each has a negligible effect on price.  In a perfectly competitive market:  All goods exactly the same  Buyers & sellers so numerous that no one can affect market price—each is a “price taker”  In this chapter, we assume markets are perfectly competitive. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 3 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand  The quantity demanded of any good is the amount of the good that buyers are willing and able to purchase.  Law of demand: the claim that the quantity demanded of a good falls when the price of the good rises, other things equal © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 4 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  The Demand Schedule Price Quantity  Demand schedule: of of lattes a table that shows the lattes demanded relationship between the $0.00 16 price of a good and the 1.00 14 quantity demanded 2.00 12 3.00 10  Example: 4.00 8 Helen’s demand for lattes. 5.00 6  Notice that Helen’s 6.00 4 preferences obey the law of demand. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 5 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Helen’s Demand Schedule & Curve Price of Price Quantity Lattes of of lattes lattes demanded $6.00 $0.00 16 $5.00 1.00 14 $4.00 2.00 12 3.00 10 $3.00 4.00 8 $2.00 5.00 6 $1.00 6.00 4 $0.00 Quantity 0 5 10 15 of Lattes © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 6 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Market Demand versus Individual Demand  The quantity demanded in the market is the sum of the quantities demanded by all buyers at each price.  Suppose Helen and Ken are the only two buyers in the Latte market. (Qd = quantity demanded) Price Helen’s Qd Ken’s Qd Market Qd $0.00 16 + 8 = 24 1.00 14 + 7 = 21 2.00 12 + 6 = 18 3.00 10 + 5 = 15 4.00 8 + 4 = 12 5.00 6 + 3 = 9 6.00 4 + 2 = 6  The Market Demand Curve for Lattes Qd P P (Market) $6.00 $0.00 24 $5.00 1.00 21 $4.00 2.00 18 3.00 15 $3.00 4.00 12 $2.00 5.00 9 $1.00 6.00 6 $0.00 Q 0 5 10 15 20 25 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 8 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters  The demand curve shows how price affects quantity demanded, other things being equal.  These “other things” are non-price determinants of demand (i.e., things that determine buyers’ demand for a good, other than the good’s price).  Changes in them shift the D curve… © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 9 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters: # of Buyers  Increase in # of buyers increases quantity demanded at each price, shifts D curve to the right. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 10 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters: # of Buyers P Suppose the number $6.00 of buyers increases. $5.00 Then, at each P, Qd will increase $4.00 (by 5 in this example). $3.00 $2.00 $1.00 $0.00 Q 0 5 10 15 20 25 30 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 11 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters: Income  Demand for a normal good is positively related to income.  Increase in income causes increase in quantity demanded at each price, shifts D curve to the right. (Demand for an inferior good is negatively related to income. An increase in income shifts D curves for inferior goods to the left.) © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 12 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters: Prices of Related Goods  Two goods are substitutes if an increase in the price of one causes an increase in demand for the other.  Example: pizza and hamburgers. An increase in the price of pizza increases demand for hamburgers, shifting hamburger demand curve to the right.  Other examples: Coke and Pepsi, laptops and desktop computers, CDs and music downloads © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 13 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters: Prices of Related Goods  Two goods are complements if an increase in the price of one causes a fall in demand for the other.  Example: computers and software. If price of computers rises, people buy fewer computers, and therefore less software. Software demand curve shifts left.  Other examples: college tuition and textbooks, bagels and cream cheese, eggs and bacon © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 14 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters: Tastes  Anything that causes a shift in tastes toward a good will increase demand for that good and shift its D curve to the right.  Example: The Atkins diet became popular in the ’90s, caused an increase in demand for eggs, shifted the egg demand curve to the right. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 15 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Demand Curve Shifters: Expectations  Expectations affect consumers’ buying decisions.  Examples:  If people expect their incomes to rise, their demand for meals at expensive restaurants may increase now.  If the economy sours and people worry about their future job security, demand for new autos may fall now. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 16 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Summary: Variables That Influence Buyers Variable A change in this variable… Price …causes a movement along the D curve # of buyers …shifts the D curve Income …shifts the D curve Price of related goods …shifts the D curve Tastes …shifts the D curve Expectations …shifts the D curve © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 17 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 1 Demand Curve Draw a demand curve for music downloads. What happens to it in each of the following scenarios? Why? A. The price of iPods falls B. The price of music downloads falls C. The price of CDs falls © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 1 A. Price of iPods falls Music downloads Price of and iPods are music down- complements. loads A fall in price of iPods shifts the P1 demand curve for music downloads to the right. D1 D2 Q1 Q2 Quantity of music downloads © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 1 B. Price of music downloads falls Price of music The D curve down- does not shift. loads Move down along P1 curve to a point with lower P, higher Q. P2 D1 Q1 Q2 Quantity of music downloads © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 1 C. Price of CDs falls Price of CDs and music music downloads down- are substitutes. loads A fall in price of CDs P1 shifts demand for music downloads to the left. D2 D1 Q2 Q1 Quantity of music downloads © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply  The quantity supplied of any good is the amount that sellers are willing and able to sell.  Law of supply: the claim that the quantity supplied of a good rises when the price of the good rises, other things equal © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 22 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  The Supply Schedule Price Quantity  Supply schedule: of of lattes A table that shows the lattes supplied relationship between the $0.00 0 price of a good and the 1.00 3 quantity supplied. 2.00 6 3.00 9  Example: 4.00 12 Starbucks’ supply of lattes. 5.00 15  Notice that Starbucks’ 6.00 18 supply schedule obeys the law of supply. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 23 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Starbucks’ Supply Schedule & Curve Price Quantity of of lattes P lattes supplied $6.00 $0.00 0 $5.00 1.00 3 $4.00 2.00 6 3.00 9 $3.00 4.00 12 $2.00 5.00 15 $1.00 6.00 18 $0.00 Q 0 5 10 15 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 24 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. Market Supply versus Individual Supply  The quantity supplied in the market is the sum of the quantities supplied by all sellers at each price.  Suppose Starbucks and Jitters are the only two sellers in this market. (Qs = quantity supplied) Price Starbucks Jitters Market Qs $0.00 0 + 0 = 0 1.00 3 + 2 = 5 2.00 6 + 4 = 10 3.00 9 + 6 = 15 4.00 12 + 8 = 20 5.00 15 + 10 = 25 6.00 18 + 12 = 30  The Market Supply Curve QS P (Market) P $6.00 $0.00 0 1.00 5 $5.00 2.00 10 $4.00 3.00 15 $3.00 4.00 20 $2.00 5.00 25 6.00 30 $1.00 $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 26 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply Curve Shifters  The supply curve shows how price affects quantity supplied, other things being equal.  These “other things” are non-price determinants of supply.  Changes in them shift the S curve… © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 27 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply Curve Shifters: Input Prices  Examples of input prices: wages, prices of raw materials.  A fall in input prices makes production more profitable at each output price, so firms supply a larger quantity at each price, and the S curve shifts to the right. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 28 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply Curve Shifters: Input Prices P Suppose the $6.00 price of milk falls. $5.00 At each price, $4.00 the quantity of $3.00 lattes supplied will increase $2.00 (by 5 in this $1.00 example). $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 29 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply Curve Shifters: Technology  Technology determines how much inputs are required to produce a unit of output.  A cost-saving technological improvement has the same effect as a fall in input prices, shifts S curve to the right. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 30 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply Curve Shifters: # of Sellers  An increase in the number of sellers increases the quantity supplied at each price, shifts S curve to the right. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 31 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply Curve Shifters: Expectations  Example:  Events in the Middle East lead to expectations of higher oil prices.  In response, owners of Texas oilfields reduce supply now, save some inventory to sell later at the higher price.  S curve shifts left.  In general, sellers may adjust supply* when their expectations of future prices change. (*If good not perishable) © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 32 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Summary: Variables that Influence Sellers Variable A change in this variable… Price …causes a movement along the S curve Input Prices …shifts the S curve Technology …shifts the S curve # of Sellers …shifts the S curve Expectations …shifts the S curve © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 33 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 2 Supply Curve Draw a supply curve for tax return preparation software. What happens to it in each of the following scenarios? A. Retailers cut the price of the software. B. A technological advance allows the software to be produced at lower cost. C. Professional tax return preparers raise the price of the services they provide. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 2 A. Fall in price of tax return software Price of tax return S curve does S1 software not shift. P1 Move down along the curve P2 to a lower P and lower Q. Q2 Q1 Quantity of tax return software © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 2 B. Fall in cost of producing the software Price of tax return S1 S curve shifts software S2 to the right: at each price, P1 Q increases. Q1 Q2 Quantity of tax return software © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 2 C. Professional preparers raise their price Price of tax return software S1 This shifts the demand curve for tax preparation software, not the supply curve. Quantity of tax return software © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Supply and Demand Together P $6.00 D S Equilibrium: P has reached $5.00 the level where $4.00 quantity supplied $3.00 equals quantity demanded $2.00 $1.00 $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 38 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Equilibrium price: the price that equates quantity supplied with quantity demanded P $6.00 D S P QD QS $5.00 $0 24 0 $4.00 1 21 5 2 18 10 $3.00 3 15 15 $2.00 4 12 20 $1.00 5 9 25 $0.00 6 6 30 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 39 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Equilibrium quantity: the quantity supplied and quantity demanded at the equilibrium price P $6.00 D S P QD QS $5.00 $0 24 0 $4.00 1 21 5 2 18 10 $3.00 3 15 15 $2.00 4 12 20 $1.00 5 9 25 $0.00 6 6 30 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 40 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Surplus (a.k.a. excess supply): when quantity supplied is greater than quantity demanded P Example: $6.00 D Surplus S If P = $5, $5.00 then $4.00 QD = 9 lattes $3.00 and QS = 25 lattes $2.00 resulting in a $1.00 surplus of 16 lattes $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 41 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Surplus (a.k.a. excess supply): when quantity supplied is greater than quantity demanded P $6.00 D Surplus S Facing a surplus, sellers try to increase $5.00 sales by cutting price. $4.00 This causes $3.00 QD to rise and QS to fall… $2.00 …which reduces the surplus. $1.00 $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 42 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Surplus (a.k.a. excess supply): when quantity supplied is greater than quantity demanded P $6.00 D Surplus S Facing a surplus, sellers try to increase $5.00 sales by cutting price. $4.00 This causes $3.00 QD to rise and QS to fall. $2.00 Prices continue to fall until market reaches $1.00 equilibrium. $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 43 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Shortage (a.k.a. excess demand): when quantity demanded is greater than quantity supplied P $6.00 D S Example: If P = $1, $5.00 then $4.00 QD = 21 lattes $3.00 and QS = 5 lattes $2.00 resulting in a $1.00 shortage of 16 lattes $0.00 Shortage Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 44 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Shortage (a.k.a. excess demand): when quantity demanded is greater than quantity supplied P $6.00 D S Facing a shortage, sellers raise the price, $5.00 causing QD to fall $4.00 and QS to rise, $3.00 …which reduces the $2.00 shortage. $1.00 Shortage $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 45 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Shortage (a.k.a. excess demand): when quantity demanded is greater than quantity supplied P $6.00 D S Facing a shortage, sellers raise the price, $5.00 causing QD to fall $4.00 and QS to rise. $3.00 Prices continue to rise $2.00 until market reaches equilibrium. $1.00 Shortage $0.00 Q 0 5 10 15 20 25 30 35 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 46 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Three Steps to Analyzing Changes in Eq’m To determine the effects of any event, 1. Decide whether event shifts S curve, D curve, or both. 2. Decide in which direction curve shifts. 3. Use supply—demand diagram to see how the shift changes eq’m P and Q. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 47 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  EXAMPLE: The Market for Hybrid Cars P price of S1 hybrid cars P1 D1 Q Q1 quantity of hybrid cars © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 48 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  EXAMPLE 1: A Shift in Demand EVENT TO BE ANALYZED: P Increase in price of gas. S1 STEP 1: P2 D curve shifts because STEP 2: price of gas P1 affects demand for D shifts right hybrids. because STEP 3: high gas S curve price doeshybrids makes not D1 D2 The shift shift, causes because an price more attractive Q increase of gas in price does not cars. Q1 Q2 relative to other and quantity affect cost of of hybrid cars. producing hybrids. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 49 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  EXAMPLE 1: A Shift in Demand Notice: P When P rises, S1 producers supply a larger quantity P2 of hybrids, even though the S curve P1 has not shifted. Always be careful D1 D2 to distinguish b/w a shift in a curve Q Q1 Q2 and a movement along the curve. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 50 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  Terms for Shift vs. Movement Along Curve  Change in supply: a shift in the S curve occurs when a non-price determinant of supply changes (like technology or costs)  Change in the quantity supplied: a movement along a fixed S curve occurs when P changes  Change in demand: a shift in the D curve occurs when a non-price determinant of demand changes (like income or # of buyers)  Change in the quantity demanded: a movement along a fixed D curve occurs when P changes © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 51 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  EXAMPLE 2: A Shift in Supply EVENT: New technology reduces cost of P producing hybrid cars. S1 S2 STEP 1: S curve shifts because STEP 2: event affects P1 cost of production. S shifts right P2 D curve does because event not STEPbecause shift, 3: reduces cost, D1 The shift causes production technology makes production Q price is not to onefallof the Q1 Q2 more profitable at and quantity factors that to rise. affect any given price. demand. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 52 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  EXAMPLE 3: A Shift in Both Supply EVENTS: and Demand Price of gas rises AND P new technology reduces S1 S2 production costs STEP 1: P2 Both curves shift. P1 STEP 2: Both shift to the right. STEP 3: D1 D2 Q rises, but effect Q on P is ambiguous: Q1 Q2 If demand increases more than supply, P rises. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 53 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  EXAMPLE 3: A Shift in Both Supply EVENTS: and Demand price of gas rises AND P new technology reduces S1 S2 production costs STEP 3, cont. P1 But if supply increases more P2 than demand, D1 D2 P falls. Q Q1 Q2 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 54 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 3 Shifts in supply and demand Use the three-step method to analyze the effects of each event on the equilibrium price and quantity of music downloads. Event A: A fall in the price of CDs Event B: Sellers of music downloads negotiate a reduction in the royalties they must pay for each song they sell. Event C: Events A and B both occur. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 3 A. Fall in price of CDs The market for STEPS P music downloads 1. D curve shifts S1 2. D shifts left P1 3. P and Q both P2 fall. D2 D1 Q Q2 Q1 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 3 B. Fall in cost of royalties STEPS The market for P music downloads 1. S curve shifts S1 S2 (Royalties are part 2. S shifts right of sellers’ costs) P1 3. P falls, Q rises. P2 D1 Q Q1 Q2 © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  ACTIVE LEARNING 3 C. Fall in price of CDs and fall in cost of royalties STEPS STEPS 1. 1. Both Both curves curves shift shift (see (see parts parts AA && B). B). 2. D shifts 2. D shifts left, left, SS shifts shifts right. right. 3. 3. PP unambiguously unambiguously falls. falls. Effect Effect on on Q Q is is ambiguous: ambiguous: The The fall fall in in demand demand reduces reduces Q,Q, the the increase increase in in supply supply increases increases Q. Q. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  CONCLUSION: How Prices Allocate Resources  One of the Ten Principles from Chapter 1: Markets are usually a good way to organize economic activity.  In market economies, prices adjust to balance supply and demand. These equilibrium prices are the signals that guide economic decisions and thereby allocate scarce resources. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as 59 permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  SUMMARY A competitive market has many buyers and sellers, each of whom has little or no influence on the market price. Economists use the supply and demand model to analyze competitive markets. The downward-sloping demand curve reflects the law of demand, which states that the quantity buyers demand of a good depends negatively on the good’s price. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  SUMMARY Besides price, demand depends on buyers’ incomes, tastes, expectations, the prices of substitutes and complements, and number of buyers. If one of these factors changes, the D curve shifts. The upward-sloping supply curve reflects the Law of Supply, which states that the quantity sellers supply depends positively on the good’s price. Other determinants of supply include input prices, technology, expectations, and the # of sellers. Changes in these factors shift the S curve. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  SUMMARY The intersection of S and D curves determines the market equilibrium. At the equilibrium price, quantity supplied equals quantity demanded. If the market price is above equilibrium, a surplus results, which causes the price to fall. If the market price is below equilibrium, a shortage results, causing the price to rise. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.  SUMMARY We can use the supply-demand diagram to analyze the effects of any event on a market: First, determine whether the event shifts one or both curves. Second, determine the direction of the shifts. Third, compare the new equilibrium to the initial one. In market economies, prices are the signals that guide economic decisions and allocate scarce resources. © 2012 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.