Principles of Microeconomics: Final Exam Study Guide

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.

• Definition: A market is any structure that allows buyers and sellers to exchange any type of goods, services, and information.

• Example: The stock market, farmers' markets, and online marketplaces.

How Do Buyers Behave?

Buyers make decisions based on preferences, budget constraints, and the prices of goods and services.

• Law of Demand: As the price of a good increases, the quantity demanded decreases, ceteris paribus.

• Demand Curve: Graphically shows the relationship between price and quantity demanded.

Individual Demand and Market Demand

Individual demand refers to the quantity of a good a single consumer is willing to buy at various prices, while market demand aggregates all individual demands.

• Market Demand: Sum of all individual demands for a good or service.

• Equation: $Q_D = q_1 + q_2 + ... + q_n$

How Do Sellers Behave?

Sellers aim to maximize profit by choosing how much to produce and at what price to sell.

• Law of Supply: As the price of a good increases, the quantity supplied increases, ceteris paribus.

• Supply Curve: Shows the relationship between price and quantity supplied.

Individual Supply, Supply Schedule, and Supply Curve

Individual supply is the quantity a single producer is willing to sell at various prices. The supply schedule lists quantities supplied at different prices, and the supply curve graphs this relationship.

Market Supply and Market Equilibrium

Market supply is the sum of all individual supplies. Market equilibrium occurs where quantity demanded equals quantity supplied.

• Equilibrium Price: The price at which the market clears ($Q_D = Q_S$).

• Equation: $Q_D(P^*) = Q_S(P^*)$

The Difference Between Qd and D

Qd refers to quantity demanded at a specific price, while D refers to the entire demand curve.

Two Types of Market Disequilibrium

• Surplus: Quantity supplied exceeds quantity demanded.

• Shortage: Quantity demanded exceeds quantity supplied.

Chapter 6: Sellers and Incentives

Seller's Problem

Sellers face the challenge of deciding how much to produce, what inputs to use, and at what cost.

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

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

• Optimum Choice: The level of output that maximizes profit.

Production Function and Marginal Product

The production function shows the relationship between inputs and output. Marginal product is the additional output from one more unit of input.

• Equation: $Q = f(L, K)$

• Marginal Product of Labor: $MP_L = \frac{\Delta Q}{\Delta L}$

Cost Functions

Cost functions describe how total cost changes with output.

• Fixed Costs (FC): Costs that do not vary with output.

• Variable Costs (VC): Costs that change with output.

• Total Cost (TC): $TC = FC + VC$

• Average Cost (AC): $AC = \frac{TC}{Q}$

• Marginal Cost (MC): $MC = \frac{\Delta TC}{\Delta Q}$

Accounting vs. Economic Profit

Accounting profit considers only 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

In the long run, firms enter or exit the market until economic profit is zero, leading to efficient allocation of resources.

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.

• Inefficient Points: Inside the curve.

• Impossible Points: Outside the curve.

Opportunity Cost

Opportunity cost is the value of the next best alternative forgone when making a choice.

• Equation: $\text{Opportunity Cost of Good X} = \frac{\text{Loss of Good Y}}{\text{Gain of Good X}}$

Comparative Advantage

A country or individual has a comparative advantage in producing a good if it can produce it at a lower opportunity cost than others.

• Example: If Country A can produce wheat at a lower opportunity cost than Country B, Country A has a comparative advantage in wheat.

Terms of Trade

Terms of trade refer to the rate at which goods are exchanged between countries.

Trade Between Sums and Equations of PPC

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

Winners and Losers of Nations

Trade creates winners (those who benefit from specialization and exchange) and losers (those who face increased competition).

Chapter 9: Externalities and Public Goods

Externalities

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

• Negative Externality: Imposes costs (e.g., pollution).

• Positive Externality: Provides benefits (e.g., education).

Private Solutions to Externalities

Private solutions include negotiation and contracts between affected parties (e.g., Coase Theorem).

Government Solutions to Externalities

Government can address externalities through taxes, subsidies, and regulation.

• Example: Carbon tax to reduce pollution.

Public Goods

Public goods are non-excludable and non-rivalrous, meaning one person's use does not reduce availability to others.

• Examples: National defense, public parks.

Free Rider Problem

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

Common Resource Goods and Tragedy of the Commons

Common resources are rivalrous but non-excludable, often leading to overuse and depletion (tragedy of the commons).

Chapter 12: Monopoly

Key Characteristics of Monopoly

A monopoly is a market with a single seller and no close substitutes for the product.

• Barriers to Entry: Factors that prevent other firms from entering the market (e.g., patents, control of resources).

Profit Maximization in Monopoly

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

• Equation: $MR = MC$

Inefficiencies of Monopoly

Monopolies can lead to higher prices, lower output, and deadweight loss compared to competitive markets.

Price Discrimination

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

• Types: First-degree (perfect), second-degree, and third-degree price discrimination.