Microeconomics Final Exam Study Guide: Markets, Sellers, Trade, Externalities, and Monopoly

Chapter 4: Demand, Supply, and Equilibrium

The Meaning of Markets

Markets are institutions or arrangements where buyers and sellers interact to exchange goods and services. They play a central role in determining prices and allocating resources efficiently.

• Market: Any mechanism that brings together buyers and sellers.

• Example: Farmers' markets, stock exchanges, online platforms.

How Buyers Behave

Buyers make decisions based on preferences, prices, and available income, aiming to maximize their utility.

• Utility: Satisfaction or benefit derived from consuming goods and services.

• Rational Choice: Buyers compare costs and benefits to make optimal decisions.

Law of Demand, Demand Schedule, and Demand Curve

The law of demand states that, ceteris paribus, as the price of a good increases, the quantity demanded decreases.

• Demand Schedule: A table showing quantities demanded at different prices.

• Demand Curve: A graphical representation of the demand schedule, typically downward sloping.

• Equation: $Q_d = f(P)$ where $Q_d$ is quantity demanded and $P$ is price.

• Example: If the price of apples rises, fewer apples are purchased.

The Difference Between Qd and D

Quantity demanded (Qd) refers to a specific amount at a given price, while demand (D) refers to the entire relationship between price and quantity demanded.

• Qd: Movement along the demand curve.

• D: Shift of the demand curve due to changes in income, tastes, etc.

Individual Demand and Market Demand

Individual demand is the demand of a single consumer, while market demand is the sum of all individual demands.

• Market Demand: $Q_{market} = \sum Q_{individual}$

• Example: If three people each buy 2 apples, market demand is 6 apples.

How Sellers Behave

Sellers aim to maximize profit by considering costs, prices, and market conditions.

• Profit: Difference between total revenue and total cost.

• Rational Decision: Sellers supply more at higher prices.

Law of Supply, Supply Schedule, and Supply Curve

The law of supply states that, ceteris paribus, as the price of a good increases, the quantity supplied increases.

• Supply Schedule: Table showing quantities supplied at different prices.

• Supply Curve: Upward sloping graph of supply schedule.

• Equation: $Q_s = f(P)$ where $Q_s$ is quantity supplied.

The Difference Between Qs and S

Quantity supplied (Qs) is the amount supplied at a specific price, while supply (S) is the entire relationship between price and quantity supplied.

• Qs: Movement along the supply curve.

• S: Shift of the supply curve due to changes in technology, input prices, etc.

Individual Supply and Market Supply

Individual supply is the supply from a single seller; market supply is the sum of all individual supplies.

• Market Supply: $Q_{market} = \sum Q_{individual}$

Market Equilibrium

Market equilibrium occurs where quantity demanded equals quantity supplied, determining the equilibrium price and quantity.

• Equilibrium: $Q_d = Q_s$

• Example: At $P^*$, buyers and sellers agree on the same quantity.

Two Types of Market Disequilibrium

Disequilibrium occurs when the market is not at equilibrium, resulting in either excess supply or excess demand.

• Excess Supply (Surplus): $Q_s > Q_d$

• Excess Demand (Shortage): $Q_d > Q_s$

Changes in Market Equilibrium

Market equilibrium can shift due to changes in demand or supply, affecting price and quantity.

• Demand Increase: Equilibrium price and quantity rise.

• Supply Increase: Equilibrium price falls, quantity rises.

Chapter 6: Sellers and Incentives

Seller’s Problem

Sellers face the problem of how to maximize profit given constraints such as input costs and production technology.

• Profit Maximization: Choosing output level where marginal cost equals marginal revenue.

Three Pillars of Rational Decision for Producers

Producers make decisions based on inputs, costs, and the optimum production level.

• Inputs: Resources used in production (labor, capital, materials).

• Costs: Expenses incurred in production (fixed and variable costs).

• Optimum Production Level: Output where profit is maximized.

• Equation: $\text{Profit} = \text{Total Revenue} - \text{Total Cost}$

Law of Diminishing Returns

The law of diminishing returns states that as more of one input is added, holding others constant, the additional output from each extra unit decreases.

• Example: Adding more workers to a fixed-size factory increases output less and less.

Finding the Optimum Quantity and Profit/Loss Area on Graph

Optimal quantity is where marginal cost equals marginal revenue. The profit/loss area is the difference between total revenue and total cost.

• Equation: $MR = MC$ (Marginal Revenue equals Marginal Cost)

• Profit Area: Area between price and average total cost, multiplied by quantity.

Shutdown or Staying in Business Decisions in Case of Loss

Firms decide to shut down or stay based on whether revenue covers variable costs.

• Shutdown Rule: If $P < AVC$ (Price less than Average Variable Cost), shut down.

• Stay in Business: If $P \geq AVC$, continue operating.

Difference Between Accounting and Economic Profit

Accounting profit considers explicit costs, while economic profit includes both explicit and implicit costs.

• Accounting Profit: $\text{Total Revenue} - \text{Explicit Costs}$

• Economic Profit: $\text{Total Revenue} - (\text{Explicit Costs} + \text{Implicit Costs})$

Producer Surplus

Producer surplus is the difference between the price sellers receive and the minimum price they are willing to accept.

• Equation: $\text{Producer Surplus} = \text{Total Revenue} - \text{Total Variable Cost}$

Competitive Equilibrium in the Long Run (Firm Entries and Exits)

In the long run, firms enter or exit the market based on profitability, leading to zero economic profit in competitive markets.

• Entry: Profitable markets attract new firms.

• Exit: Unprofitable markets lose firms.

Chapter 8: Trade

Production Possibilities Curve (PPC)

The PPC shows the maximum combinations of two goods that can be produced with available resources and technology.

• Efficient Points: On the curve; resources fully utilized.

• Possible Points: On or inside the curve.

• Impossible Points: Outside the curve; unattainable with current resources.

Calculating the Opportunity Cost on PPC

Opportunity cost is the value of the next best alternative foregone. On the PPC, it is measured by the slope.

• Equation: $\text{Opportunity Cost} = \frac{\text{Loss in Good A}}{\text{Gain in Good B}}$

Comparative Advantage Theory

Comparative advantage exists when a country can produce a good at a lower opportunity cost than another.

• Specialization: Countries specialize in goods where they have comparative advantage.

• Example: If Denmark produces cheese at lower opportunity cost than butter, it should specialize in cheese.

Acceptable Terms of Trade for International Trade

Terms of trade are the rate at which goods are exchanged internationally, falling between the opportunity costs of trading partners.

• Example: If Denmark's opportunity cost of cheese is 2 butter, and Germany's is 4 butter, terms of trade must be between 2 and 4 butter per cheese.

Trade Between States and Expansion of PPC

Trade allows countries to consume beyond their own PPC by specializing and exchanging goods.

• Expansion: Consumption possibilities increase with trade.

Determinants of Trade Between Countries

Factors such as comparative advantage, resource endowments, and government policies determine whether a country is an exporter or importer.

• Example: Denmark exports goods where it has comparative advantage.

Chapter 9: Externalities and Public Goods

Externalities (Negative and Positive)

Externalities are costs or benefits that affect third parties not involved in a transaction.

• Negative Externality: Harmful effect (e.g., pollution).

• Positive Externality: Beneficial effect (e.g., education).

Pecuniary Externalities

Pecuniary externalities occur when market transactions affect others through price changes rather than direct physical effects.

• Example: Increased demand for housing raises prices for others.

Private Solutions to Externalities

Private parties can resolve externalities through negotiation, contracts, or property rights (Coase Theorem).

• Coase Theorem: If property rights are well-defined and transaction costs are low, private solutions are possible.

Government Solution to Externalities

Governments address externalities through taxes, subsidies, regulation, and tradable permits.

• Tax: Imposed on negative externalities (e.g., carbon tax).

• Subsidy: Provided for positive externalities (e.g., education grants).

• Regulation: Setting limits or standards.

• Tradable Permits: Allow firms to buy/sell rights to pollute.

Public Goods and Characteristics of Four Types of Goods

Goods are classified based on excludability and rivalry. The four types are public goods, private goods, common pool resources, and club goods.

Type of Good	Excludable?	Rival?	Example
Private Goods	Yes	Yes	Food, clothing
Public Goods	No	No	National defense, clean air
Common Pool Resources	No	Yes	Fish stocks, forests
Club Goods	Yes	No	Cable TV, private parks

Free Rider Problem

The free rider problem occurs when individuals benefit from a good without paying for it, leading to under-provision of public goods.

• Example: People enjoy national defense without contributing to its cost.

Common Pool Resource Goods and Tragedy of the Commons

Common pool resources are susceptible to overuse, leading to depletion (tragedy of the commons).

• Example: Overfishing in public waters.

Chapter 12: Monopoly

Key Characteristics of Monopoly

A monopoly is a market with a single seller, unique product, and significant barriers to entry.

• Single Seller: Only one firm supplies the market.

• Unique Product: No close substitutes.

• Price Maker: Monopoly sets the price.

Barriers to Entry

Barriers to entry prevent other firms from entering the market.

• Legal Barriers: Patents, licenses.

• Resource Control: Ownership of key resources.

• Economies of Scale: Large firms have cost advantages.

Profit Maximization in Monopoly

Monopolists maximize profit by producing where marginal revenue equals marginal cost.

• Equation: $MR = MC$

• Price: Set above marginal cost.

The Inefficiencies of Monopoly

Monopolies cause inefficiency by restricting output and charging higher prices, resulting in deadweight loss.

• Deadweight Loss: Loss of total surplus due to monopoly pricing.

• Equation: $\text{Deadweight Loss} = \text{Total Surplus under Competition} - \text{Total Surplus under Monopoly}$

Price Discrimination

Price discrimination occurs when a monopoly charges different prices to different consumers for the same product.

• First-degree: Each consumer pays their maximum willingness to pay.

• Second-degree: Price varies by quantity purchased.

• Third-degree: Price varies by consumer group (e.g., student discounts).