曼昆经济学原理chapt1chapt15笔记整理.docx

1、曼昆经济学原理chapt1chapt15笔记整理Chapter 1: Introduction前言1. Society allocates people to various jobs and the output of goods and services.2. Scarcity means that resources are limited so cannot produce all the goods and services people want.3. Economics is the study of how society manages its scare resources

2、.4. Economists study 3 things: How people make decisions How people interact with one another Analyze forces and trends that affect the economy as a wholeHow people make decisions (10 principles)1. People face trade-off1) Making decisions requires trading off one goal against another.2) Trade-off so

3、ciety faces: Guns and butter; a clean environment and a high level of income Efficiency and equitymaximum benefits and fair2. The cost of sth is what you give up to get it1) Opportunity cost: what you give up to get that item3. Rational people think at the margin1) They systematically and purposeful

4、ly do the best to achieve their objectives2) Marginal changes are adjustments around the edges of what you are doing3) Rational people make decisions by comparing marginal benefits and costs4) Peoples willingness to pay for any good is the marginal benefit of an extra unit of the good would bring4.

5、People respond to incentives1) Public policymakersincentivespolicies change peoples behavior. E.g. taxHow people interact5. Trade can make everyone better off1) Allow countries to specialize in what they do best and to enjoy more goods6. Markets are usually a good way to organize economic activity1)

6、 Market economy is more successful2) The invisible hand is price which adjust to maximize the welfare of society7. Governments can sometimes improve market outcomes1) Reasons why we need G Invisible hand works only if property rights are enforced Invisible hand is powerful but not omnipotent全能的; pol

7、icies aim to promote both efficiency and equityMarket failurea situation in which the market on its own fails to produce an efficient allocation of resources. Causes: externality and market power Invisible hand fail to ensure that economic prosperity is distributed equitablyHow the economy as a whol

8、e works8. A countrys standard of living depends on its ability to produce goods and services1) Productivitythe quantity of goods and services produced from each hour of a workers timeproductivity high, living standard high 2) Far-reaching and public policy will implicate the relationship between pro

9、ductivity and living srandard9. Prices rise when the G prints too many money1) Keep inflation at a low level2) Growth in the amount of money causes inflation10. Society faces a short-run trade-off between inflation and unemployment1) Business cyclefluctuations in economic activity, such as employmen

10、t and productionChapter 2: Thinking like an economist1. The scientific method: observationtheorymore observationadvanced theory2. Economists make assumptions because they can simplify the complex world and make it easier to understand3. Economists use diff. assumptions to answer diff. Qs4. Economist

11、s use models, which are built with assumptions and composed of diagrams and equations, to learn about the worldModel 1: the circular-flow diagramonly two types of decision makersfirms and householdsModel 2: the production possibilities frontier1) The shape of PPF is bowed outward2) On PPFefficiency

12、level of production; In or out off PPTinefficiency3) PPF shows the opportunity cost of one good as measured in terms of the other good4) The opportunity cost of products quantity is reflected in the shape of the PPF5. Positive VS normative analysisPS: descriptive; claims about how the world isscient

13、istsNS: prescriptive; claims about how the world ought to bepolicy advisers6. The field of economics is divided into microeconomics and macroeconomics7. Differences in scientific judgments or values cause the conflictions between economists who advise policymakerChapter 4: The market forces of suppl

14、y and demandMarket and competition1. Market1) Buyers and sellersdemand and supply2) Highly organized and less organized marketagricultural commodities and ice cream market2. Perfectly competition market1) Goods are exactly the same2) So numerous buyers and sellersno single one will influence the mar

15、ket price3) Buyers and sellers are price takers, and can buy or sell all they want4) e.g. wheat market, ice cream market 5) Economists use the model of supply and demand to analyze this market Demand1. Quantity demanded: the amount of good that buyers are willing and able to buy1) The quantity deman

16、ded is negatively related to the priceprice rises, quantity demanded fallsprice affect a movement along the demand curve2) Market demand is the sum of all the individuals demands for a good2. Demand curve: what happens to the quantity demanded of a good when the price varies3. Curve shifts when ther

17、e is a change in a relevant variable that is not measured on either axis4. Shifts in demand curve (right, increase in demand; left, decrease)1) Income Normal good (include necessity and luxury): income fallsdemand falls (positive correlation); e.g. ice cream Inferior good: income fallsdemand rises (

18、negative correlation); e.g. to ride a bus2) Prices of related goods Substitutes: price of one good falls, demand of another good reducepairs of goods in place of each other; e.g. hot dogs and hamburgers Complements: price of one good falls, demand of another good raisespairs of goods used together;

19、e.g. computer and software3) Tastes: the most obvious determinant of the demand; likebuy more4) Expectations Expect higher incomesave lessbuy more today Expect higher pricebuy more today5) Numbers of buyers: more members, shift to rightSupply1. Quantity supplied is the amount that sellers are willin

20、g and able to sellpositive related to the goods pricechange of price lead to supplys change2. Market supply is the sum of the supplies of all sellersadd all of the suppliers3. Shifts in the supply curve1) Input pricesinputs price rises substantially, shift to left2) Technologyadvance in technology,

21、raise the supply3) Expectationsfirm, price rise in the future, supply less4) Number of sellersmore members, higher supplyEquilibrium 1. Equilibrium: market piece has reached the level at which quantity supplied=quantity demandedthe quantity of goods buyers are willing and able to buy=sellers are wil

22、ling and able to sell2. Equilibrium price=market-clearing priceeveryone in the market has been satisfieddetermines how much of the good buyers choose to purchase and how much sellers choose to produce3. Actual priceE pricesurplus=excess supplyquantity suppliedquantity demandedsellers cut the pricein

23、crease quantity demanded and decrease quantity supplied4. Market priceE priceshortage=excess demandquantity suppliedquantity demandedsellers raise the pricequantity demanded falls and quantity supplied rises5. Law of supply and demand: the price of any good adjusts to bring the quantity supplied and

24、 quantity demanded for that good into balance6. How quickly prices adjust determine how quickly equilibrium is reached; vary from market to market7. Surpluses and shortages in free market are temporaryThree steps to analyzing changes in E1. Decide whether the events shifts the supply or demand curve

25、 (or perhaps both)2. Decide in which direction the curve shifts3. Use the supply-and-demand diagram to see how the shift changes the equilibrium price and quantity (compare new E with the initial E)4. A shift in the supply/demand curve=change in supply/demand; a movement along a fixed supply/demand

26、curve=change in the quantity supplied/demanded5. No changes in SAn increase in SA decrease in SNo change in DP, Q sameP down, Q upP up, Q downAn increase in DP up, Q upP ambiguous, Q upP up, Q ambi.A decrease in DP down, Q downP down, Q ambiguousP ambi., Q downConclusion1. Supply and demand together

27、 determine the prices of goods, price in turn guide the allocation of resources2. Prices determine who buys each good and how much is producedChapter 5: Elasticity and its applicationThe price elasticity of demand1. Determinant of the price elasticity of demandMore elastic demandLess elastic demandG

28、oods with close substitutese.g. butter and margarineWithoute.g. eggsLuxuriesNecessitiesNarrowly defined markete.g. ice creamBroadly defined markete.g. foodLonger time horizonsShorter time horizons2. Price elasticity of demand=% change in quantity demanded/% change in price3. A larger price elasticit

29、ya greater responsiveness of quantity demanded to price4. Midpoint method: a better wayPrice elasticity of demand=(Q2-Q1)/(Q2+Q1)/(P2-P1)/(P2+P1)5. The variety of demand curves: the flatter the demand curve that passes through a given point, the greater the price elasticity of demand1) Perfectly ine

30、lastic: elasticity=0, demand curve is vertical2) Inelastic: elasticity1, demand curve seems flat Price and total revenue move in opposite directions5) Perfectly elastic: elasticity=infinity, demand curve is horizontal6. The slope of a linear demand curve=1 while the elasticity is not the same along the entire curve.7. Other demand ela