AP Microeconomics Unit Review

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==Unit 1== ==: Introduction to Economics==

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@@1.1 : Scarcity@@

  • Economics : study of scarcity and choice
  • Individual choice : given scarcity, individuals make decisions about what to do and not to do
  • Scarcity : unlimited wants, limited resources (example : land)
  • Positive statement : true statement (what is)
  • Normative statement : opinionated statement  (what should be)

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@@1.2: Resource Allocation and Economic Systems@@

  • Market economy : individual producers and consumers decide what/how/and for whom to produce (limited government intervention)
  • Command economy : publicly owned, a central authority will make decisions for production and consumption (has government intervention)
  • Property rights : establish ownership and grants individuals the right to trade goods/services with each other
  • Resources : anything that can be used to produce something else
  • Factors of production :
    • land (natural resources),
    • labor (the effort of workers),
    • capital (all manufactured resources),
    • entrepreneurship (risk taking, innovation, and organization)
  • Opportunity cost : value of the next-best alternative that you give up to make another choice
  • Microeconomics : individuals/households/firms making decisions and how those decisions interact (ex : college vs. a job)
  • Macroeconomics : behavior of the economy as a whole (ex: employment)

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@@1.3: Production Possibilities Curve@@

  • Production possibilities curve (PPC) : illustrates the trade-offs that faces an economy, compares only two goods

  • Trade-offs : giving up something for something else

  • If the PPC is linear, it has a constant opportunity cost, if it is curved, it has increasing opportunity costs

  • Economic growth : a sustained rise in aggregate output and an increase in standard of living (causes are developments in technology, or an increase in resources)

  • Productive efficiency : lowest cost possible on the PPC

  • Allocative efficiency : the economy allocates resources so consumers are well off as possible, producing what is demanded

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@@1.4: Comparative Advantage and Trade@@

  • Trade : people split up the work, and provide each other with a good in return for another
  • Comparative advantage : lower opportunity cost in the production of a good (you cannot have a comparative advantage in both goods)
  • Absolute advantage : higher output

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@@1.5: Cost-Benefit Analysis@@

  • Terms of Trade : the rate at which one good can be exchanged for another (if the price of a good obtained from trade is less than the opportunity cost of producing it, trade is beneficial)
  • Capital goods: goods that make consumer goods (ex. machinery)
  • Consumer goods : goods that are consumed (ex. food)

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@@1.6: Marginal Analysis and Consumer Choice@@

  • Utility : the measure of personal satisfaction (util is a unit of utility)
  • Marginal utility : the change in total utility by consumer one additional unit of that good/service
  • Principle of diminishing marginal utility : additional units of a good/service add less total utility than the previous units do
  • Marginal utility per dollar : MUgood/Pgood (marginal utility of one unit of the good / price of one unit of the good)
  • Optimal consumption rule : to maximize utility, marginal utility per dollar spend on each good = service in consumption bundle, MUc/Pc = MUt/Pt

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==Unit 2==  ==: Supply and Demand==

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@@2.1: Demand@@

  • Demand is downwards sloping

  • Law of demand : As price increases, demand decreases, and as price decreases, demand increases

  • Movement along the curve : change in price

  • Shifters of demand :

    • Tastes,
    • related goods (substitutes + complements),
    • income (normal + inferior goods),
    • (# of) buyers,
    • expectation of future prices
    • (TRIBE)
  • Substitution effect : as the price of a good increases, consumers substitute the good with another that is cheaper

  • Substitutes : good/service that can be used in place of another, when price of one increases, consumers will buy more of the other (ex. coffee and tea)

  • Complements : goods/services that are consumed together (ex. hamburgers and buns)

  • Income effect : as income increases, people will buy more of normal goods, and less of inferior goods

  • Normal good : increase in demand when consumer’s income increases (ex. oreos)

  • Inferior good : increase in demand when consumer’s income decreases (ex. off brand oreos)

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@@2.2 : Supply@@

  • Supply is upwards sloping

  • Law of supply : as price increases, quantity supplied also increases

  • Movement along the curve : change in price

  • Shifters of supply :

    • input prices,
    • (price of) related goods/services,
    • (producer) expectations
    • , number of producers
    • , technology
    • (I-RENT)

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@@2.3: Price Elasticity of Demand@@

  • Equation : %∆Qd/%∆P

    • 0 = perfectly elastic,
  • Midpoint formula : Qd2-Qd1/(Q2d+Qd1)/2 , replace with Qd with price for price

  • Inelastic demand : TR correlates direct with price

  • Elastic demand = TR correlates inversely with price

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@@2.4: Price Elasticity of Supply@@

  • Equation : %∆Qs/%∆P

  • 0 = perfectly elastic,

  • Inelastic : unable to respond to price change

  • Elastic : short run

  • Extremely elastic : long run

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@@2.5: Other Elasticities@@

  • Cross price elasticity of demand : %∆Qd of Good A/%∆P of good B
  • negative = compliments, positive = substitutes
  • Income elasticity of demand : %∆Qd/%∆income
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1 = income elastic, <1 = income inelastic, negative = inferior, positive = normal

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@@2.6: Market Equilibrium and Consumer and Producer Surplus@@

  • Equilibrium : occurs when no one is better off doing something else

  • Equilibrium = Qs=Qd

  • Price below the equilibrium is shortage

  • Consumer surplus : price consumers are willing to pay - actual price

  • Producer surplus : actual price -price the producer is willing to sell for

  • Demand increase : price and quantity increase

  • Demand decrease : price and quantity decrease

  • Supply increase : price decreases, quantity increases

  • Supply decrease : price increases, quantity decreases

  • Double shift : either price or quantity will be unknown

  • Deadweight loss (DWL) : transactions that should occur, but don’t because of government intervention (calculate the area = triangle formula, ½(base x height)

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@@2.7: Market Disequilibrium and Changes in Equilibrium + 2.8: The Effects of Government Intervention in Markets@@

  • Shortage : Qs < Qd, price is lower than equilibrium

  • Surplus : Qs > Qd, price is above equilibrium

  • Price floor : minimum price a supplier can charge, price is set above equilibrium (causes shortage)

  • Price ceiling : maximum price a supplier can charge, price is set below equilibrium (causes surplus)

  • Double shift rule : when supply and demand both shift, either price or quantity will be unknown

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  • Quota : upper limit of a quantity that can be bought or sold (known as quantity control)

  • License : gives an owner the right to supply a good/service

  • Demand price : the price at which consumers will demand that quantity

  • Supply price : the price at which producers will supply that quantity

  • Quota rent : difference between demand price and supply price

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@@2.9: International Trade and Public Policy@@

  • Tariffs : tax placed on a good that is imported or exported

  • Import quota : restriction on the quantity of a good that can be imported

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==Unit 3:== ==Production, Cost, and the Perfect Competition Model==

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@@3.1: The Production Function@@

  • Production function : relation between the quantity of inputs a firm uses and the quantity of output it produces
  • Fixed input : an input whose quantity doesn’t change
  • Variable input : an input whose quantity can change
  • Long run : time period in which all inputs can be variable
  • Short run : time period in which at least 1 input is fixed
  • Marginal product : change in overall output when input changes
  • Marginal product of labor (MPL) : ∆Q/∆L
  • Diminishing marginal returns : as input increases, the output of each input will be less than the previous input
  • Output : quantity produced
  • Rental rate : price of capital
  • Capital : goods that are used to produce goods/services

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@@3.2: Short-Run Production Costs@@

  • Fixed cost : cost that doesn’t change with amount of output produced (ex. oven)

  • Variable cost : cost that changes with amount of output produced

  • Total cost : fixed cost + variable cost

  • Marginal cost : cost difference of one additional unit of output (∆TC/∆Q)

  • Average fixed cost (AFC) : FC/Q

  • Average variable cost (AVC) : VC/Q

  • Average total cost (ATC) : TC/Q

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@@3.3: Long-Run Production Costs@@

  • Long run average total cost (LRATC) : same as short run ATC, but bigger

  • Economies of scale : LRATC declines as output increases

  • Diseconomies of scale : LRATC increaess as output increases

  • Constant returns to scale : output increase directly in proportion to an increase in all inputs (ex. input doubles, output also doubles)

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@@3.4: Types of Profit@@

  • Economic profit : revenue - explicit cost - implicit cost, or accounting profit - implicit cost
  • Accounting profit : revenue - explicit cost
  • Implicit cost : not an actual cost, a cost that you could’ve been earning (ex. if you own a restaurant, the implicit cost would be the salary you would have earned as being a chef working in a different restaurant)

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@@3.5: Profit Maximization@@

  • MR = MC
  • If you cannot have MR=MC, MR>MC

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@@3.6: Firms’ Short-Run Decisions to Produce and Long-Run Decisions to Enter or Exit a Market@@

Short Run:

  • Shutdown rule : as long as P > AVC, continue to produce
  • If AVC > P : shutdown
  • Firms can make profit or losses

Long Run :

  • Exit rule : if P < ATC, exit the market
  • Firms make normal profit ($0), unless monopoly or oligopoly

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@@3.7: Perfect Competition@@

  • Many firms, identical products, low/no barriers to advertisement

  • Price takers

  • Long run will have normal profit

  • Short run can have either profit or loss

==Unit 4:== ==Imperfect Competition==

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@@4.1: Introduction to Imperfectly Competitive Markets@@

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Perfect CompetitionMonopolistic CompetitionMonopolyOligopoly
# of firmsManyMany1Few
Type of productStandardDifferentiatedUniqueStandard or different
Price controlNoneLittleYesSome
Barriers to entryNoneNone (few)HighHigh

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  • Common barriers to entry : control of scarce resources, legal barriers, high startup costs

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@@4.2: Monopoly@@

  • Only producer of a good, has no close substitutes

  • Downwards sloping demand curve

  • Quantity is produced : @ MR = MC

  • Price is : MR=MC, up to demand

  • Supply curve : where MC > AVC

  • Allocatively efficient due to them producing at MR=MC

  • Productively inefficient because they don’t produce at the minimum of the ATC

  • Natural monopoly : has large fixed costs, and long economies of scale, has downward sloping ATC curve

  • Natural monopoly production point : MR=MC

  • Government will correct by forcing them to set price : @ ATC=D

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@@4.3: Price Discrmination@@

  • To be able to price discriminate, you need market power

  • Imperfect price discrimination : chargine consumers different prices based on the buyer’s willingness to pay

  • Perfect price discrimnation : charges all consumers the maximum they are willing to pay, no deadweight loss, produce @ P=MC

  • Example : resellers, coupons, bulk buying (costco), etc.

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@@4.4: Monopolistic Competition@@

Characteristics

  • Combines features of both a monopoly and perfect competition

  • Many sellers and differentiated products

  • Will use advertising to make demand more inelastic + differentiate product

  • Makes profit in short run, normal profit in long run

  • Allocatively inefficient (P does not equal MC)

  • Productively inefficient (does not produce @ minimum of ATC, until long run)

  • Downwards sloping demand curve

  • Produce at MR = MC, price is MR = MC up to demand

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Long Run

  • Normal profit in long run

  • Short run profits will attract new firms to join, which decreases the demand until the demand Curve is tangent to ATC, causing normal profits in long run

  • In long run, they produce in region where economies of scales exist, because they produce in declining portion of ATC

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@@4.5: Oligopoly and Game Theory@@

Oligopoly Characteristics

  • Small number of firms, standard or differentiated product
  • Interdependent : all the actions that a firm takes will affect the other firms in the oligopoly (if They ask why the market is an oligopoly, say it’s because they’re interdependent)
  • Cartels : a group that agrees to control the price and output of a product (often form in oligopoly)
  • Collusion : working together to maximize profit
  • Graph is almost identical to monopoly (you will never be asked to draw them)
  • Also produce same quantity and price of monopoly

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Game Theory

  • Payoff matrix : represents the payoff to each player to show combinations of given strategies

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Player B
Choice 1Choice 2
Player AChoice 1A1,B1A2,B2
Choice 2A3,B3A4,B4
  • Dominant strategy : the strategy that has a better payoff regardless of what strategy the opponent chooses
  • Nash equilibrium : point where both players can do no better than the other given the choice of their opponent

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==Unit 5: Factor Markets==

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@@5.1: Introduction of Factor Markets@@

  • Derived demand : the demand from a resource is derived by product demand
  • Marginal revenue product (MRP) : the additional revenue that is generated by an additional resource/worker
  • Marginal factor cost (MFC) : the additional cost of an additional resource/worker
  • Least cost rule : marginal product of labor/price of labor = marginal product of capital/price of capital (MPL/PL=MPK/PK)
  • Buy more of the one with a higher sum, and less of the one with a smaller sum (to explain, as you increase, diminishing marginal returns kicks in)

@@5.2: Changes in Factor Demand and Factor Supply@@

  • Shifters of demand for labor
    • Change in demand for the product
    • Change in the productivity of the resource
    • Change in price of substitutes and complements
  • Shifters of supply for labor
    • # of qualified workers (ex. immigrants)
    • Government regulation
    • Leisure (causes supply to shift to left)

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@@5.3: Profit-Maximizing Behavior in Perfectly Competitive Factor Markets@@

  • Market curve : standard supply and demand curve

  • Equilibrium wage in the market : establishes the wage that firms will pay workers

  • MRP=MRC!!!!

  • will not hire if MRC>MRP

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@@5.4: Monopsonistic Markets@@

  • Many sellers, one buyer
  • Monopsonies pay a lower wage and hire less than perfect competition
  • MRP=MFC
  • MFC > supply
  • example of imperfect competition

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==Unit 6: Market Failure and the Role of Government==

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@@6.1: Socially Efficient and Inefficient Market Outcomes@@

  • Socially efficiency is when resources are allocated effectively
  • MSB=MSC !!
  • Allocatively Efficient Points
    • Perfectly competitive market : S=D, MB=MC
    • Perfectly competitive firm : P=MC
    • Perfectly competitive labor market : W=MRP (total economic surplus : MSC=MSB)
  • Causes of Market Failure
    • Market power (imperfectly competitive markets)
    • Asymmetric information (lack of info provided by buyers and sellers)
    • Positive and negative externalities
    • Insufficient production of public goods
  • Government policies used to get rid of DWL
    • Taxes
    • Subsidies
    • Reguations
    • Public prodivions
  • Market failure : exists when firms produce @ MPC=MPC, S=D
  • The government tries to get them to produce @ MSC =MSB

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@@6.2: Externalities@@

  • Externality : when external cost/benefit is placed on members of society who did not pay for them

  • MSB does not equal MSC

  • Negative externality : when someone uses a product, it decreases the benefit of others (ex. smoking), MSC > MPC (correct with per unit tax)

  • Positive externality : when one uses a product, others benefit  (ex. education) MSC < MPC (correct with subsidy)

@@6.3: Public and Private Goods@@

  • Rivalrous good : if someone consumers a product, others cannot
    • Rivalrous : food, shoes, etc
    • Nonrivalrous : national defense, fireworks, etc
    • Somewhere in middle : schools, roads, etc
  • Excludable good : non payers can be prevented from enjoying the benefits
    • Excludable : food, school, etc
    • Nonexcludable : national defense, air, etc
  • Public goods : underproduced due to freeloader problem
  • Examples : national defense, law enforcement, etc
  • Freeloader problem : people can enjoy the benefit of a good/service without paying
  • Government will provide subsidies to producers
  • Private goods : goods produced by private markets, can be excludable

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@@6.4: The Effects of Government Intervention in Different Market Structures@@

  • Causes of inefficient markets

    • Market power
    • Externalities
    • Nonrival and nonexcludable goods (public goods)
  • Forms of government intervention

    • Taxes
    • Subsidies
    • Price floors/ceilings
    • Regulation
  • Per unit subsidy : gives benefits per unit

    • Perfect competition : MC, ATC, AVC decreases, price doesn’t change (price taker)
    • Monopolistic competition : MC, ATC, price decreases (price maker @ MR=MC)
  • Lump sum subsidy : gives benefit no matter how many units

  • Taxes will always shift supply curve to the left in long run, profits decrease

  • Per unit tax : increase MC, ATC, and AVC

    • Perfect competition : MC, ATC, AVC increases, price doesn’t change (price taker)
    • Monopolistic competition : MC, ATC, price increases (price maker @ MR=MC)
  • Lump sum tax : only increase ATC

  • won’t change output level

  • Non price regulation : works like taxes, they ensure competition/environmental protection/health and safety

  • Antitrust policy : promote competition and prevents monopolies

  • Antitrust laws

    • Lawsuits
    • Price controls
    • Subsidies
  • Price ceiling : sets minimum price

    • Perfect competition : causes shortage
    • Monopolistic competition : becomes MR curve, price and output decreases
  • Price floor : sets maximum price

    • Perfect competition : leads to surplus
    • Monopsony : wages go up and workers go up

6.5: Inequality

  • Income distribution : measures % of income that goes to individuals in different percentiles/brackets
  • In a system with perfectly equality : everyone would receive equal shares of income
  • Income : wages, rent, interest, profit
  • Lorenz curve : measures the distribution of income equality  (you want to be as close of possible to the perfect equality line as possible)
  • Gini coefficient : A/(A+B)
    • Closer to 0, more equality
    • Closer to 1, the more inequality
  • Causes of income inequality
    • Supply + demand in labor market
    • Human capital
    • Discrimination
    • Inheritance
    • Bargaining power
    • Etc
  • Policies to address inequality
    • Taxes + transfers
    • Minimum wage laws
    • Anti-poverty program
    • Income protection program
    • Scholarships
  • Taxes :
    • Proportional : everyone pays the same percentage of their income (no impact on income distribution)
    • Progressive : taxes are higher % on people earning a higher income (reduces income inequality)
    • Regressive : taxes are lower % on people earning a higher income (increases income inequality)

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