《西方经济学》双语ppt课件.ppt

Thinking Like An Economist,2,CHAPTER 2 THINKING LIKE AN ECONOMIST,In this chapter,look for the answers to these questions:,What are economists two roles?How do they differ?What are models?How do economists use models?What are the elements of the Circular-Flow Diagram?What concepts does this diagram illustrate?How is the Production Possibilities Frontier related to opportunity cost?What other concepts does it illustrate?What is the difference between microeconomics and macroeconomics?Between positive and normative?,CHAPTER 2 THINKING LIKE AN ECONOMIST,The Economist as Scientist,Economists play two roles:Scientists:try to explain the worldPolicy advisors:try to improve itIn the first role,economists employ the scientific method:the dispassionate development and testing of theories about how the world works.,CHAPTER 2 THINKING LIKE AN ECONOMIST,Assumptions&Models,Assumptions simplify the complex world,make it easier to understand.Example:When studying international trade,we might assume the world consists of two countries and two goods.Very unrealistic,but simplifies the problem and yields useful insights about the more complicated real world.Economists use models to study economic issues.A model is a highly simplified representation of a more complicated reality.,CHAPTER 2 THINKING LIKE AN ECONOMIST,Some Familiar Models,A road map,CHAPTER 2 THINKING LIKE AN ECONOMIST,Some Familiar Models,A model of human anatomy from high school biology class,CHAPTER 2 THINKING LIKE AN ECONOMIST,Some Familiar Models,A model airplane,CHAPTER 2 THINKING LIKE AN ECONOMIST,Some Familiar Models,The model teeth at the dentists office,CHAPTER 2 THINKING LIKE AN ECONOMIST,Our First Model:The Circular-Flow Diagram,The Circular-Flow Diagram:A visual model of the economy,shows how dollars flow through markets among households and firms.Includes two types of“actors”:householdsfirms Includes two markets:the market for goods and services the market for“factors of production”,CHAPTER 2 THINKING LIKE AN ECONOMIST,Factors of Production,The factors of production are the resources that the economy uses to produce goods&services.They include:labor land capital(buildings&machines used in production),CHAPTER 2 THINKING LIKE AN ECONOMIST,FIGURE 1:The Circular-Flow Diagram,Households:own the factors of production,sell/rent them to firms for incomebuy and consume goods&services,CHAPTER 2 THINKING LIKE AN ECONOMIST,FIGURE 1:The Circular-Flow Diagram,Households,Firms:buy/hire factors of production,use them to produce goods and servicessell goods&services,CHAPTER 2 THINKING LIKE AN ECONOMIST,FIGURE 1:The Circular-Flow Diagram,CHAPTER 2 THINKING LIKE AN ECONOMIST,Our Second Model:The Production Possibilities Frontier,The Production Possibilities Frontier(PPF):A graph that shows the combinations of two goods the economy can possibly produce given the available resources and the available technology.Example:Two goods:computers and wheatOne resource:labor(measured in hours)Economy has 50,000 labor hours per month available for production.,0,PPF Example,Producing one computer requires 100 hours labor.Producing one ton of wheat requires 10 hours labor.,0,CHAPTER 2 THINKING LIKE AN ECONOMIST,A,B,C,D,E,PPF Example,A C T I V E L E A R N I N G 1:Points on the PPF,A.On the graph,find the point that represents(100 computers,3000 tons of wheat),label it F.Would it be possible for the economy to produce this combination of the two goods?Why or why not?B.Next,find the point that represents(300 computers,3500 tons of wheat),label it G.Would it be possible for the economy to produce this combination of the two goods?,16,A C T I V E L E A R N I N G 1:Answers,17,Point F:100 computers,3000 tons wheat,Point F requires 40,000 hours of labor.Possible but not efficient:could get more of either good w/o sacrificing any of the other.,A C T I V E L E A R N I N G 1:Answers,18,Point G:300 computers,3500 tons wheat,Point G requires 65,000 hours of labor.Not possible because economy only has 50,000 hours.,CHAPTER 2 THINKING LIKE AN ECONOMIST,The PPF:What We Know So Far,Points on the PPF(like A E)possibleefficient:all resources are fully utilizedPoints under the PPF(like F)possiblenot efficient:some resources underutilized(e.g.,workers unemployed,factories idle)Points above the PPF(like G)not possible,CHAPTER 2 THINKING LIKE AN ECONOMIST,The PPF and Opportunity Cost,Recall:The opportunity cost of an item is what must be given up to obtain that item.,Moving along a PPF involves shifting resources(e.g.,labor)from the production of one good to the other.Society faces a tradeoff:Getting more of one good requires sacrificing some of the other.The slope of the PPF tells you the opportunity cost of one good in terms of the other.,CHAPTER 2 THINKING LIKE AN ECONOMIST,The PPF and Opportunity Cost,The slope of a line equals the“rise over the run”the amount the line rises when you move to the right by one unit.,1000,100,=10,Here,the opportunity cost of a computer is 10 tons of wheat.,A C T I V E L E A R N I N G 2:PPF and Opportunity Cost,22,In which country is the opportunity cost of cloth lower?,FRANCE,ENGLAND,A C T I V E L E A R N I N G 2:Answers,23,England,because its PPF is not as steep as Frances.,FRANCE,ENGLAND,CHAPTER 2 THINKING LIKE AN ECONOMIST,Economic Growth and the PPF,With additional resources or an improvement in technology,the economy can produce more computers,more wheat,or any combination in between.,Economic growth shifts the PPF outward.,CHAPTER 2 THINKING LIKE AN ECONOMIST,The Shape of the PPF,The PPF could be a straight line,or bow-shapedDepends on what happens to opportunity cost as economy shifts resources from one industry to the other.If opp.cost remains constant,PPF is a straight line.(In the previous example,opp.cost of a computer was always 10 tons of wheat.)If opp.cost of a good rises as the economy produces more of the good,PPF is bow-shaped.,CHAPTER 2 THINKING LIKE AN ECONOMIST,Why the PPF Might Be Bow-Shaped,As the economy shifts resources from beer to mountain bikes:PPF becomes steeperopp.cost of mountain bikes increases,CHAPTER 2 THINKING LIKE AN ECONOMIST,A,Why the PPF Might Be Bow-Shaped,At point A,most workers are producing beer,even those that are better suited to buildingmountain bikes.So,do not have to give up much beer to get more bikes.,Mountain Bikes,Beer,At A,opp.cost of mtn bikes is low.,CHAPTER 2 THINKING LIKE AN ECONOMIST,B,Why the PPF Might Be Bow-Shaped,At B,most workers are producing bikes.The few left in beer are the best brewers.Producing more bikes would require shifting some of the best brewers away from beer production,would cause a big drop in beer output.,Mountain Bikes,Beer,At B,opp.cost of mtn bikes is high.,CHAPTER 2 THINKING LIKE AN ECONOMIST,Why the PPF Might Be Bow-Shaped,So,PPF is bow-shaped when different workers have different skills,different opportunity costs of producing one good in terms of the other.The PPF would also be bow-shaped when there is some other resource,or mix of resources with varying opportunity costs.E.g.,different types of land suited for different uses,CHAPTER 2 THINKING LIKE AN ECONOMIST,The PPF:A Summary,The PPF shows all combinations of two goods that an economy can possibly produce,given its resources and technology.,The PPF illustrates the concepts of tradeoff and opportunity cost,efficiency and inefficiency,unemployment,and economic growth.,A bow-shaped PPF illustrates the concept of increasing opportunity cost.,CHAPTER 2 THINKING LIKE AN ECONOMIST,Microeconomics and Macroeconomics,Microeconomics is the study of how households and firms make decisions and how they interact in markets.Macroeconomics is the study of economy-wide phenomena,including inflation,unemployment,and economic growth.These two branches of economics are closely intertwined,yet distinct:they address different questions.,CHAPTER 2 THINKING LIKE AN ECONOMIST,The Economist as Policy Advisor,As scientists,economists make positive statements,which attempt to describe the world as it is.As policy advisors,economists make normative statements,which attempt to prescribe how the world should be.Positive statements can be confirmed or refuted,normative statements cannot.Govt employs many economists for policy advice.E.g.,the U.S.President has a Council of Economic Advisors,which the author of this textbook recently chaired.,A C T I V E L E A R N I N G 3:Identifying positive vs.normative,Which of these statements are“positive”and which are“normative”?How can you tell the difference?a.Prices rise when the government increases the quantity of money.b.The government should print less money.c.A tax cut is needed to stimulate the economy.d.An increase in the price of gasoline will cause an increase in consumer demand for video rentals.,33,A C T I V E L E A R N I N G 3:Answers,a.Prices rise when the government increases the quantity of money.Positive,describes a relationship,could use data to confirm or refute.b.The government should print less money.Normative,this is a value judgment,cannot be confirmed or refuted.,34,A C T I V E L E A R N I N G 3:Answers,c.A tax cut is needed to stimulate the economy.Normative,another value judgment.d.An increase in the price of gasoline will cause an increase in consumer demand for video rentals.Positive,describes a relationship.Note that a statement need not be true to be positive.,35,CHAPTER 2 THINKING LIKE AN ECONOMIST,Why Economists Disagree,Economists often give conflicting policy advice.They sometimes disagree about the validity of alternative positive theories about the world.They may have different values and,therefore,different normative views about what policy should try to accomplish.Yet,there are many propositions about which most economists agree.,CHAPTER 2 THINKING LIKE AN ECONOMIST,Propositions about Which Most Economists Agree(and%agreeing),A ceiling on rents reduces the quantity and quality of housing available.(93%)Tariffs and import quotas usually reduce general economic welfare.(93%)A large federal budget deficit has an adverse effect on the economy.(83%)A minimum wage increases unemployment among young and unskilled workers.(79%)Effluent taxes and marketable pollution permits represent a better approach to pollution control than imposition of pollution ceilings.(78%),CHAPTER 2 THINKING LIKE AN ECONOMIST,FYI:Who Studies Economics?,Ronald Reagan,President of the United StatesBarbara Boxer,U.S.Senator Sandra Day-OConnor,Supreme Court JusticeAnthony Zinni,General,U.S.Marine Corps Kofi Annan,Secretary General,United NationsMeg Witman,Chief Executive Officer,eBaySteve Ballmer,Chief Executive Officer,MicrosoftJohn Elway,NFL QuarterbackTiger Woods,GolferBen Stein,Political Speechwriter,Actor,Game Show HostArnold Schwarzenegger,Governor of California,ActorMick Jagger,Singer for the Rolling Stones,CHAPTER 2 THINKING LIKE AN ECONOMIST,CHAPTER SUMMARY,As scientists,economists try to explain the world using models with appropriate assumptions.Two simple models are the Circular-Flow Diagram and the Production Possibilities Frontier.Microeconomics studies the behavior of consumers and firms,and their interactions in markets.Macroeconomics studies the economy as a whole.As policy advisers,economists offer advice on how to improve the world.,