Final Exam Study Guide: Principles of Microeconomics (Key Concepts)

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Chapter 4: Demand, Supply, and Equilibrium

Law of Demand, Demand Schedule, and Demand Curve

The law of demand states that, all else equal, as the price of a good increases, the quantity demanded decreases, and vice versa. The demand schedule is a table showing the quantity demanded at each price, while the demand curve is a graphical representation of this relationship.

Law of Demand: Inverse relationship between price and quantity demanded.
Demand Schedule: Tabular data showing price and corresponding quantity demanded.
Demand Curve: Downward-sloping curve on a price-quantity graph.
Example: If the price of coffee rises from $2 to $3, the quantity demanded falls from 100 to 80 cups.

Market Equilibrium

Market equilibrium occurs where the quantity demanded equals the quantity supplied at a particular price. This is the point where there is no tendency for price to change.

Equilibrium Price: The price at which demand equals supply.
Equilibrium Quantity: The quantity bought and sold at equilibrium price.
Formula:
Example: If at $5, both buyers and sellers agree to exchange 50 units, $5 is the equilibrium price.

The Definition of Markets

A market is any arrangement that allows buyers and sellers to exchange goods, services, or resources. Markets can be physical or virtual.

Key Point: Markets facilitate voluntary exchange.
Example: Farmers' market, stock market, online marketplaces.

Law of Supply, Supply Schedule, and Supply Curve

The law of supply states that, all else equal, as the price of a good increases, the quantity supplied increases. The supply schedule is a table showing the quantity supplied at each price, and the supply curve is its graphical representation.

Law of Supply: Direct relationship between price and quantity supplied.
Supply Schedule: Tabular data showing price and corresponding quantity supplied.
Supply Curve: Upward-sloping curve on a price-quantity graph.
Example: If the price of wheat rises, farmers supply more wheat.

Market Disequilibrium: Surplus and Shortage

When the market price is not at equilibrium, there can be a surplus (excess supply) or a shortage (excess demand).

Surplus: Quantity supplied exceeds quantity demanded; price tends to fall.
Shortage: Quantity demanded exceeds quantity supplied; price tends to rise.
Example: If price is set above equilibrium, unsold goods accumulate (surplus).

Outside Factors Affecting Demand and Shifts of Demand Curve

Factors other than price, such as income, tastes, prices of related goods, and expectations, can shift the demand curve.

Increase in Demand: Demand curve shifts right.
Decrease in Demand: Demand curve shifts left.
Example: If consumer income rises, demand for normal goods increases.

Chapter 6: Sellers and Incentives

Producer Surplus

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

Formula:
Example: If a seller is willing to sell at $4 but receives $6, producer surplus is $2.

Total, Fixed, and Variable Cost

Costs are classified as fixed (do not vary with output), variable (change with output), and total cost (sum of fixed and variable costs).

Fixed Cost (FC): Costs that remain constant regardless of output.
Variable Cost (VC): Costs that change with the level of production.
Total Cost (TC):
Example: Rent is a fixed cost; raw materials are variable costs.

Key Characteristics of Perfectly Competitive Markets

A perfectly competitive market has many buyers and sellers, homogeneous products, free entry and exit, and perfect information.

Many Participants: No single buyer or seller can influence price.
Homogeneous Products: Goods are identical.
Free Entry/Exit: Firms can freely enter or leave the market.
Perfect Information: All participants know prices and product quality.
Example: Agricultural markets for wheat or corn.

Total and Marginal Revenue

Total revenue is the total income from sales; marginal revenue is the additional revenue from selling one more unit.

Total Revenue (TR):
Marginal Revenue (MR):
Example: Selling 10 units at $5 each yields $50 total revenue.

Profit Maximization and the Optimality Rule (MC = MR)

Firms maximize profit by producing the quantity where marginal cost equals marginal revenue.

Optimality Rule:
Example: If MC is $10 and MR is $10, the firm is maximizing profit at that output.

Short-run vs. Long-run Planning

The short run is a period in which at least one input is fixed; the long run is when all inputs can be varied.

Short Run: Some factors (like capital) are fixed.
Long Run: All factors are variable; firms can enter or exit the market.
Example: In the short run, a factory cannot expand its building; in the long run, it can.

Chapter 12: Monopoly

The Definition of Monopoly

A monopoly is a market structure with a single seller of a unique product with no close substitutes.

Key Point: Monopolist has market power to set prices.
Example: Local water utility company.

Barriers to Entry, Natural Monopolies, Economies of Scale

Barriers to entry prevent new firms from entering the market. Natural monopolies arise when economies of scale make a single firm most efficient.

Barriers: Legal restrictions, control of resources, high startup costs.
Natural Monopoly: One firm can supply the market at lower cost than multiple firms.
Example: Electricity distribution.

Benefits of Certain Monopolies

Some monopolies may provide benefits, such as economies of scale or innovation due to high profits.

Key Point: Monopolies can invest in research and development.
Example: Pharmaceutical patents encourage drug development.

Comparison of Different Market Structures

Market structures differ in number of firms, product differentiation, and market power.

Perfect Competition: Many firms, no market power.
Monopoly: One firm, significant market power.
Example: Wheat market vs. local utility.

Price Discrimination: Types, Characteristics, and Examples

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

Types: First-degree (personalized), second-degree (quantity discounts), third-degree (group pricing).
Example: Student discounts, airline tickets.

Social Cost and Deadweight Loss Resulting from Monopoly

Monopolies can create deadweight loss by restricting output and raising prices, reducing total welfare.

Deadweight Loss: Loss of total surplus due to inefficient allocation.
Formula:
Example: Fewer consumers buy a product at monopoly prices.

Chapter 9: Externalities and Public Goods

Properties of Goods: Rivalry and Excludability

Goods are classified by rivalry (whether one person's use diminishes another's) and excludability (whether people can be prevented from using it).

Private Goods: Rival and excludable (e.g., food).
Public Goods: Non-rival and non-excludable (e.g., national defense).
Common Goods: Rival but non-excludable (e.g., fisheries).
Club Goods: Non-rival but excludable (e.g., subscription services).

Type of Good	Rival?	Excludable?	Example
Private	Yes	Yes	Food
Public	No	No	National Defense
Common	Yes	No	Fishery
Club	No	Yes	Streaming Service

Common Goods (Resources), Tragedy of the Commons, and Solutions

Common goods are resources accessible to all, leading to overuse and depletion, known as the tragedy of the commons.

Tragedy of the Commons: Overuse of common resources due to lack of property rights.
Solutions: Regulation, privatization, or community management.
Example: Overfishing in public waters.

Externalities: Positive, Negative, and Pecuniary

Externalities are side effects of economic activity affecting third parties. They can be positive (benefits), negative (costs), or pecuniary (affect prices).

Positive Externality: Vaccination benefits others.
Negative Externality: Pollution harms others.
Pecuniary Externality: Large purchases affect market prices.
Remedies: Taxes, subsidies, regulation.

Chapter 8: Trade

Arguments Against Free Trade

Some argue against free trade due to concerns about jobs, national security, and infant industries.

Key Point: Protectionism may safeguard domestic industries but can reduce overall welfare.
Example: Tariffs imposed to protect steel industry.

Comparative Advantage and Absolute Advantage

Comparative advantage is the ability to produce a good at lower opportunity cost; absolute advantage is the ability to produce more with the same resources.

Comparative Advantage: Basis for trade; countries specialize in goods they produce most efficiently.
Absolute Advantage: Producing more output with same input.
Example: If Country A can produce both wheat and cars more efficiently, but Country B has lower opportunity cost for wheat, B has comparative advantage in wheat.

Tariffs and Their Effects on Welfare

Tariffs are taxes on imports, raising prices and reducing trade. They can protect domestic producers but often reduce consumer welfare and total surplus.

Key Point: Tariffs create deadweight loss and reduce gains from trade.
Example: Imposing a tariff on imported cars increases prices for consumers.

Trade Between Countries and Welfare Effects

Trade allows countries to specialize and increases total welfare, but may have distributional effects.

Key Point: Trade increases efficiency and consumer choice.
Example: U.S. imports electronics from Asia, benefiting consumers with lower prices.