濟(jì)寧孔子國(guó)際學(xué)校 AP 微觀經(jīng)濟(jì)學(xué)知識(shí)點(diǎn)梳理 I. Basic Economic Concepts 經(jīng)濟(jì)學(xué)基礎(chǔ)概念 (8–14%) 選擇 A.Scarcity, choice and opportunity cost 稀缺性（概念），選擇（概念），機(jī)會(huì)成本（計(jì)算） a. Scarcity(Unlimited want vs. Limited resources )→Make choices→ Economics b. Opportunity cost (The best choice you give up) include explicit and implicit cost, the slope 公式：Opportunity Cost of doing A=loss in B / gain in A c. Factors of productions are resources. B. Production possibilities curve 生產(chǎn)可能性邊界曲線（識(shí)圖，計(jì)算） 橫縱坐標(biāo)軸分別是兩種產(chǎn)品的產(chǎn)量，斜率是機(jī)會(huì)成本。 a. 曲線彎: law of increasing opportunity cost（生產(chǎn)鞋和電腦的資源不可相互替代）；because the resources are not perfectly adaptable. b. 直的: 生產(chǎn)兩種物品的資源可完全替代，也就是說資源完全可以通用，機(jī)會(huì)成本恒定。 C.Comparative advantage, absolute advantage, specialization and trade 比較優(yōu)勢(shì)（計(jì)算），絕對(duì)優(yōu)勢(shì)（計(jì)算），專業(yè)化（概念），貿(mào)易（概念） a. 絕對(duì)優(yōu)勢(shì)：more productive. 生產(chǎn)一單位less time or less input。（或者單位time或input生產(chǎn)更多）如果給的是時(shí)間，則不用換算 b. 比較優(yōu)勢(shì)：lower opportunity cost. xxx/hour 別忘了是與本國(guó)生產(chǎn)另一產(chǎn)品的opportunity cost 相比較 c. Specialization and trade can increase productivity and output. Economic growth could be achieved by: Increase in the quantity of resources Increase in the quality of existing resources Technological advancements d. Trade can be good to both countries even if one country has the absolute advantage in all products. Two countries trade only when they have comparative advantage on different good. After trading, countries gain more production at lower cost. D.Economic systems, Property rights and the role of incentives 計(jì)劃經(jīng)濟(jì)和市場(chǎng)經(jīng)濟(jì)（概念），產(chǎn)權(quán)（概念），激勵(lì)的作用（概念） Command economy:公平equitable，government determines，but sophisticated to allocate properly, lack of incentives for innovation; Free/capitalism economy: private ownership, property rights, free, incentives, competition,供求決定價(jià)格，市場(chǎng)決定生產(chǎn)多少消費(fèi)多少。如果是mixed economy，則market和government共同決定。 F. Marginal analysis 邊際思維（概念） MB>MC, 做這件事。Marginal=additional II. The Nature and Functions of Product Markets 產(chǎn)品市場(chǎng)的特點(diǎn)和功能 (55–70%) A. Supply and demand 供給和需求 (15–20%) 1. Market equilibrium 市場(chǎng)均衡 （先Q后P） Equilibrium quantity 由 Qs 和Qd決定：Qs=Qd D 的變動(dòng)才會(huì)引起P的變動(dòng) 2. Determinants of supply and demand 供給和需求的影響因素 影響需求 影響供給 Taste Tax /SubsidyCost of input Income Technology Price of substitute good Price of complement good Tax Expectation of price cost of inputs technology and productivity Subsidy/tax Expectation of price Price of other goods 切記：Price變動(dòng)導(dǎo)致沿著曲線的移動(dòng)，而不是曲線本身的移動(dòng)；上表里的因素都是導(dǎo)致曲線本身移動(dòng)的。 S,D同向移動(dòng)：左（Q減少，P不定）；右（Q增加，P不定） S,D反向移動(dòng)：內(nèi)（P增加，Q不定）；外（P減少，Q不定） 3. Price control Price ceiling: Creates shortage price floor：最低工資是經(jīng)典例子Creates surplus increase deadweight loss Welfare Analysis=consumer surplus+ producer surplus The market is efficient only when MB=MC, or total welfare is maximized. 4. Elasticity彈性 a. Price elasticity of demand Ed=(%change in quantity demanded of good x)/(%change in the price of good X) b. Price elasticity of supply 一定要分清問的是關(guān)于supply還是demand 需求和供給價(jià)格彈性算絕對(duì)值，不關(guān)心正負(fù)號(hào)；彈性為無窮時(shí)，叫Perfectly Elastic完全彈性，彈性大于1時(shí)，叫Relatively Elastic，彈性等于1時(shí)，叫Unit elastic，彈性小于1時(shí)，叫relatively inelastic，彈性等于0時(shí)，perfectly inelastic完全剛性。 應(yīng)用：彈性為elastic時(shí)，P降低，Total Revenue會(huì)增加，因?yàn)镼增加的程度大于P降低的程度；為inelastic時(shí)，P降低，Total Revenue會(huì)減少，因?yàn)镼增加的程度小于P降低的程度。 影響價(jià)格彈性的因素：奢侈品的彈性大于1，必需品的彈性小于1；時(shí)間長(zhǎng)彈性大于1；替代品多彈性大于1；占收入比重大彈性大于1。 c. Income elasticity of demand EI=(%change in quantity demanded of good X)/(%change in income) 需求收入彈性正號(hào)表示物品是normal goods，負(fù)號(hào)表示inferior goods d. Cross-price elasticity of demand Ex,y=(%change in quantity demand of good X)/(%change in price good Y) 交叉需求彈性正號(hào)表示A和B為substitution，負(fù)號(hào)表示A和B為complementary。 5. Consumer surplus, producer surplus and market efficiency剩余和市場(chǎng)效率 消費(fèi)者剩余=支付意愿–市場(chǎng)價(jià)格；生產(chǎn)者剩余=市場(chǎng)價(jià)格–生產(chǎn)成本 Market efficiency： MB=MC, Total Surplus最大 Supply do the same（longer time, more elastic） 6. Tax incidence and deadweight loss稅收負(fù)擔(dān)和無謂損失 1. monopoly Perfectly competitive market Per-unit subsidy/tax MC&ATC both change Only ATC change Lump-sum subsidy/tax Nothing change Nothing change 2.Tax 永遠(yuǎn)是向sellers 收的，只是sellers根據(jù)elasticity of demand and supply 的不同來向consumer收錢。 3.Tax or subsidy/negative, positive externality會(huì)造成deadweight loss, but shift of supply or demand curve 不會(huì)，因?yàn)樗鼈冃纬闪诵碌木恻c(diǎn)。 4.收稅之后，suppliers & demanders charge different money.(one below, one above) 5.在畫deadweight loss的時(shí)候，尖點(diǎn)永遠(yuǎn)是optimal point Trade Barriers Import when world price is lower. Export when world price is higher. Create deadweight loss TR of government=quantity imported/exported x the tariff C. Theory of consumer choice 消費(fèi)者選擇理論 (5–10%) 可能大題 1. Total utility and marginal utility 總效用和邊際效用 Utility is the satisfaction or happiness law of diminishing marginal utility 2. Utility maximization: equalizing marginal utility per dollar 邊際效用之比等于價(jià)格之比MU1/MU2 =P1/P2，在預(yù)算允許的條件下。 3. Income and substitution effects收入效應(yīng)，替代效應(yīng) Income effect：normal: 都多買或少買 substitution effect：normal: 一個(gè)多買一個(gè)少買 inferior: income decrease 多買，price increase 少買 D. Production and costs生產(chǎn)與成本 (10–15%) 1. Production functions: short and long run短期和長(zhǎng)期的生產(chǎn)函數(shù) Short run: only labor variable Long run: all variable 2. Marginal product and diminishing returns邊際產(chǎn)量和邊際產(chǎn)量遞減規(guī)律 MP of A= additional output/ additional input of A Marginal returns start diminishing when MP decreases as L increases FC不變　隨著labor的增加，MC增加（因?yàn)樯a(chǎn)力下降） MC和MP的圖！ 3.Short-run costs短期成本曲線 MC曲線最后是上揚(yáng)的，是因?yàn)椋洌椋恚椋睿椋螅瑁椋睿纭。铮妗。恚幔颍纾椋睿幔臁。穑颍铮洌酰悖簦a(chǎn)能力全部被利用之后，再增加邊際投入，就會(huì)出現(xiàn)邊際產(chǎn)量遞減，邊際成本遞增。 4. Long-run costs and economies of scale長(zhǎng)期成本曲線和規(guī)模經(jīng)濟(jì) 長(zhǎng)期有economies of scale規(guī)模經(jīng)濟(jì)，指隨著產(chǎn)量增加ATC不斷下降，反之則是diseconomies of scale規(guī)模不經(jīng)濟(jì), constant returns to scale規(guī)模收益不變指產(chǎn)量變動(dòng)而ATC不變，或者說投入增加的倍數(shù)與產(chǎn)出增加的倍數(shù)相同。 規(guī)模經(jīng)濟(jì)的產(chǎn)生是因?yàn)閟pecialization& ability to purchase 5. Cost minimizing input combination成本最小化的要素組合 MPL/PL=MPK/PK E. Firm behavior and market structure企業(yè)行為和產(chǎn)業(yè)組織 (25–35%) 必出大題 1. Profit利潤(rùn) a. Accounting profit，economic profit 會(huì)計(jì)利潤(rùn)（總收益-顯性成本）和經(jīng)濟(jì)利潤(rùn)（總收益-顯性成本-隱性成本） b. Normal profit 指的經(jīng)濟(jì)利潤(rùn)為0（但依然賺著會(huì)計(jì)利潤(rùn)） d. Profit maximization 對(duì)各種類型的企業(yè)都適用的利潤(rùn)最大化條件是當(dāng)MR=MC時(shí)的產(chǎn)量，即使沒有恰好相等的點(diǎn)，也要選擇MR剛剛大于MC的那個(gè)產(chǎn)量。 2. Perfect competition完全競(jìng)爭(zhēng) Price taker→ No economic profit in the long run a. Profit maximization P=AR是恒等式，因?yàn)镻=TR/Q,AR=TR/Q。完全競(jìng)爭(zhēng)市場(chǎng)很特別，企業(yè)獲得利潤(rùn)最大化的產(chǎn)量是在P=MC=MR=AR時(shí)。 b. Short-run supply and shutdown decision 短期的企業(yè)供給曲線是MC曲線在AVC上方的那段；在短期，如果P<AVC，企業(yè)選擇停業(yè)；市場(chǎng)長(zhǎng)期供給曲線是水平的。 c. Behavior of firms and markets in the short run and in the long run profit ?enter; loss ?exit 計(jì)算短期profit或loss時(shí)，應(yīng)找準(zhǔn)P和ATC，Profit=TR-TC=(P-ATC)*Q d. Efficiency and perfect competition 因?yàn)镻(MB)=MC，所以完全競(jìng)爭(zhēng)市場(chǎng)有效率。=64 1jhjjjjn7 3. Monopoly壟斷 特點(diǎn)：只有一家企業(yè)，因此需求曲線向右下方傾斜；自己定價(jià)，是price maker；有壁壘，因此有長(zhǎng)期經(jīng)濟(jì)利潤(rùn)。 a. Sources of market power Ownership; legal; natural(economies of scale) b. Profit maximization 先通過MR=MC的條件確定產(chǎn)量Q，再通過需求曲線找到對(duì)應(yīng)的P，這是壟斷企業(yè)利潤(rùn)最大化的條件。P=AR>MR c. Inefficiency of monopoly 壟斷無效率 因?yàn)楫a(chǎn)量少于需求并且收取高于期望的價(jià)格，所以壟斷是效率低的。too little of the production and charges too high a price. 會(huì)畫圖：知道Revenue maximizing（MR=0的產(chǎn)量），profit maximizing（MR=MC）, efficient maximizing（P=MC）與fair return企業(yè)經(jīng)濟(jì)利潤(rùn)為0（ATC和D相交）這四種情況下的產(chǎn)量和價(jià)格。 d. Price discrimination 價(jià)格歧視 1.consumer surplus=0 2.produce at allocative efficient point 3.be able to separate buyers and block them from retailing. 4. Monopolistic competition壟斷競(jìng)爭(zhēng) a.Product differentiation and role of advertising 有許多賣者，每個(gè)賣者提供略有差別的產(chǎn)品，無壁壘，有決定價(jià)格的能力，做廣告的必要性 b.Profit maximization 與壟斷類似。先通過MR=MC的條件確定產(chǎn)量Q，再通過需求曲線找到對(duì)應(yīng)的P，這是壟斷競(jìng)爭(zhēng)企業(yè)利潤(rùn)最大化的條件。P=AR>MR。 c.Short-run and long-run equilibrium 短期有profit或loss，吸引新企業(yè)進(jìn)入或舊企業(yè)退出市場(chǎng)。 進(jìn)而達(dá)到長(zhǎng)期均衡，D與ATC曲線相切，切點(diǎn)剛好是MC=MR投影到D的點(diǎn)，長(zhǎng)期利潤(rùn)為0。因?yàn)樵贏TC的下降部分相切，所以有規(guī)模經(jīng)濟(jì)。 d.Excess capacity and inefficiency 壟斷競(jìng)爭(zhēng)無效率體現(xiàn)在：產(chǎn)能過剩 Excess capacity，價(jià)格過高 P>MC 5. Oligopoly 寡頭 a.Interdependence, collusion and cartels 卡特爾、聯(lián)盟、互賴 受反托拉斯法的約束，有market power，企業(yè)數(shù)量很少；合作的話，如同壟斷一般獲利最大，如果不合作，則利潤(rùn)不高。 b.Game theory and strategic behavior 會(huì)利用支付矩陣分析占優(yōu)策略。必考。題目中可能一方有占優(yōu)策略另一方無占優(yōu)策略，那么沒有的那方要先揣測(cè)出有占優(yōu)的那方的意圖。 F. Factor Markets要素市場(chǎng). (10–18%) 出大題 1. Derived factor demand派生需求 對(duì)一種生產(chǎn)要素的需求來自（派生自）對(duì)另一種產(chǎn)品的需求。 ↑D for product→↑price of product→↑MRPL→↑hiring of labor at the current wage 2. Marginal revenue product邊際產(chǎn)量值 增加一單位勞力所引起的產(chǎn)值的變化 MRP=MP*MR=MP*P (perfectly competitive market) 3. Labor market and firms’ hiring of labor (perfectly competitive market) D=MRP曲線，MRP=P*MPL S=wage 利潤(rùn)最大化雇用人數(shù)：w=VMP=MRP=P*MP 竅門： a. 影響需求 1. product demand 2. productivity Technical progress Quantity of other resources quality of variable resources 3. prices of other resources Substitute resources Substitution effect Income effect Complementary resources b. 影響供給 changes in taste women works people who rely parents increase changes in other opportunities immigration (Monopsony) Quantity is hired when MC=MRP Price=Supply G. Market Failure and the Role of Government市場(chǎng)失靈和政府管制 (12–18%) 1. Externalities外部性，出大題 a.Marginal social benefit and marginal social cost b.Positive externalities 正外部性：MSB>MSC under allocation subsidy(per unit) lump sum subsidy has no effect on the graph. c.Negative externalities 負(fù)外部性：MSB<MSC over allocation tax 2. Public goods公共物品 excludable nonexcludable Rival Private goods Common resources nonrival Natural monopoly goods Public goods 3. Public policy to promote competition a.Antitrust policy competition b.Regulation 政府對(duì)壟斷的管制 如果政府給壟斷、壟斷競(jìng)爭(zhēng)、完全競(jìng)爭(zhēng)企業(yè)一次性補(bǔ)貼或一次性征稅（lump sum subsidy or tax），不會(huì)對(duì)企業(yè)的MC產(chǎn)生影響，因此不會(huì)影響利潤(rùn)最大化產(chǎn)量和價(jià)格。但由于影響了ATC，導(dǎo)致利潤(rùn)或loss有變化。如果征稅或補(bǔ)貼是按單位per unit，則會(huì)影響MC，繼而影響利潤(rùn)最大化產(chǎn)量和價(jià)格。 4. Income distribution促進(jìn)市場(chǎng)競(jìng)爭(zhēng)的政策 a.Equity 認(rèn)識(shí)洛倫茲曲線：是反映收入不平等程度的?；嵯禂?shù)是不規(guī)則圖形面積比上大三角面積，越小越接近公平。 b.Sources of income inequality 收入不平等的來源：歧視，教育程度不同，能力不同，動(dòng)機(jī)不同。 必背定義 Scarcity Law of increasing cost Productive efficiency Allocative efficiency Marginal utility The change in total utility that results from a one-unit increase in the quantity of a good or service consumed. law of diminishing marginal utility The general tendency for marginal utility to decrease as the quantity of a good consumed increases. Marginal product The change in total product that results from a one-unit increase in the quantity of labor employed. Increasing marginal returns When the marginal product of an additional worker exceeds the marginal product of the previous worker. Decreasing marginal returns When the marginal product of an additional worker is less than the marginal product of the previous worker. Derived demand The demand for a factor of production, which is derived from the demand for the goods and services that it is used to produce. 注意 同學(xué)們經(jīng)常錯(cuò)的知識(shí)點(diǎn) 1、 機(jī)會(huì)成本一定是備選項(xiàng)中最好的那個(gè)。在研究market時(shí)，包含explicit cost 和implicit cost。 2、 對(duì)比優(yōu)勢(shì)時(shí)，看清求絕對(duì)優(yōu)勢(shì)還是比較優(yōu)勢(shì)！比較優(yōu)勢(shì)給的是哪一種情況。 3、 一定要搞清S和D的影響因素！?。。。?！給什么分析什么。作為產(chǎn)品，互為替代品或互補(bǔ)品，影響D；但作為生產(chǎn)要素（in production）互為替代品或互補(bǔ)品，影響S。 4、 完全競(jìng)爭(zhēng)市場(chǎng)中，P vs AVC, shut down point，supply curve （short run）；P vs ATC, economic profit or loss (short run or long run) 5、 MC=MR, profit maximizing； MR=0，total revenue maximized； P=MC，market efficient； P=ATC, normal profit?economic profit=0 6、 在有外部性存在的情況下求deadweight loss！?。。。?！不能錯(cuò)！！?。。。? 7、 Tax & subsidy lump sum subsidy or tax：無論在何種市場(chǎng)里對(duì)MC都無影響，MC和MR都不變，所以P和Q不會(huì)變，但是影響ATC，所以會(huì)影響economic profit or loss。（2008.1） Per unit subsidy or tax: （2006.2；2007.1） 影響MC, 從而影響Q。 收稅/補(bǔ)貼多少。價(jià)格差多少，就收/補(bǔ)多少。 8、 不要主觀行事，客觀對(duì)待題目，給什么答什么，不能想當(dāng)然！?。。。?！