Microeconomics Exam 1 Study Guide: Chapters 1-4

Study Guide - Smart Notes

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

Cost-Benefit Principle and Opportunity Cost

Cost-Benefit Principle

The cost-benefit principle is a foundational concept in economics, guiding rational decision-making by comparing the benefits and costs of an action.

Definition: Take an action if the benefits outweigh the costs.
Marginal Analysis: Focuses on the additional (marginal) benefit and cost of one more unit.
Sunk Costs: Costs that have already been incurred and cannot be recovered; they are irrelevant to current decisions.

Opportunity Cost

Opportunity cost is the value of the next best alternative foregone when making a choice, reflecting the fundamental problem of scarcity.

Explicit Costs: Direct monetary payments.
Implicit Costs: Non-monetary sacrifices, such as time or resources.
Scarcity: Limited resources force choices and trade-offs.

Production Possibility Frontier (PPF)

The PPF is a graphical representation of the maximum combinations of two goods that can be produced given available resources and technology.

Efficient Points: Located on the PPF; all resources are fully utilized.
Inefficient Points: Inside the PPF; some resources are underutilized.
Unattainable Points: Outside the PPF; not possible with current resources.
Opportunity Cost: The slope of the PPF shows the opportunity cost of the good on the X-axis.
Productivity Shifts: Improvements in technology or resources shift the PPF outward.

Marginal Principle

The marginal principle states that decisions should be made by comparing marginal benefits (MB) and marginal costs (MC).

Rule: If , undertake the action.
Diminishing Marginal Benefits: The additional benefit from consuming one more unit typically decreases as quantity increases.

Interdependence Principle

Choices are interdependent, influenced by limited resources, the actions of others, developments in other markets, and expectations about the future.

Network Effects: The value of a product increases as more people use it.
Congestion Effects: The value decreases as usage increases (e.g., traffic).
Expectations: Anticipated future events affect current decisions.

Demand: Individual and Market

Individual Demand

Individual demand reflects a consumer's willingness to pay for a good or service, based on rational decision-making.

Willingness to Pay: The maximum price a consumer is willing to pay for a unit.
Rational Decision Rule: Buy if ; keep buying until .

Market Demand

Market demand is the sum of all individual demands for a good or service at each price level.

Horizontal Sum: Add quantities demanded by all individuals at each price.
Transition: From individual to market demand by summing across buyers.

Determinants of Demand

Income:
- Normal Goods: Demand increases as income rises.
- Inferior Goods: Demand decreases as income rises.
Preferences: Changes in tastes affect demand.
Price of Related Goods:
- Complements: Goods consumed together; demand for one increases as the price of the other falls.
- Substitutes: Goods consumed instead of each other; demand for one increases as the price of the other rises.
Expectations: Anticipated changes in price or availability affect current demand.
Congestion and Network Effects: Social and usage effects on demand.
Type and Number of Buyers: More buyers increase market demand.

Changes in Demand vs. Quantity Demanded

Change in Quantity Demanded: Movement along the demand curve due to price change.
Change in Demand: Shift of the entire demand curve due to other factors.

Supply and Producer Choice

Perfect Competition

Perfect competition is a market structure characterized by many buyers and sellers, identical products, and price-taking behavior.

Assumptions:
- Many buyers and sellers
- Identical products
- Price takers (no individual can influence price)

Individual Supply

Individual supply is determined by the marginal cost of production, including opportunity cost.

Marginal Cost: The cost of producing one additional unit.
Variable Costs: Costs that change with output; relevant for supply decisions.
Fixed Costs: Costs that do not change with output; not relevant for supply decisions.
Rational Decision Rule: Produce if .

Market Supply

Market supply is the sum of individual supplies at each price level.

Horizontal Sum: Add quantities supplied by all producers at each price.
Diminishing Marginal Product: As more inputs are used, the additional output from each input decreases.

Determinants of Supply

Productivity and Technology: Improvements shift supply outward.
Price of Related Outputs:
- Complements-in-Production: Goods produced together; supply of one increases as the price of the other rises.
- Substitutes-in-Production: Goods produced instead of each other; supply of one increases as the price of the other falls.
Expectations: Anticipated future prices affect current supply.
Type and Number of Sellers: More sellers increase market supply.

Changes in Supply vs. Quantity Supplied

Change in Quantity Supplied: Movement along the supply curve due to price change.
Change in Supply: Shift of the entire supply curve due to other factors.

Market Equilibrium and Market Types

Market Economy vs. Planned Economy

Market economies allocate resources through decentralized decisions of many firms and households, while planned economies rely on centralized government control.

Market Economy: Prices and production determined by supply and demand.
Planned Economy: Government determines prices and production.

Equilibrium

Market equilibrium occurs when quantity demanded equals quantity supplied, resulting in a stable market price.

Equilibrium Condition:
Invisible Hand: Mechanism by which markets self-adjust to equilibrium.
Shortage: When , prices tend to rise.
Surplus: When , prices tend to fall.

Predicting Market Changes

Changes in supply or demand affect equilibrium price and quantity. For exam purposes, focus on shifts in either supply or demand, not both simultaneously.

Increase in Demand: Raises equilibrium price and quantity.
Decrease in Demand: Lowers equilibrium price and quantity.
Increase in Supply: Lowers equilibrium price, raises equilibrium quantity.
Decrease in Supply: Raises equilibrium price, lowers equilibrium quantity.
Simultaneous Shifts: More complex; not the main focus for this exam.

Example Table: Effects of Shifts on Equilibrium

Change	Equilibrium Price	Equilibrium Quantity
Increase in Demand	Up	Up
Decrease in Demand	Down	Down
Increase in Supply	Down	Up
Decrease in Supply	Up	Down

Example: If a new technology increases productivity, supply shifts right, lowering price and increasing quantity.

Additional info: The study guide covers the main principles and models from Chapters 1-4, including rational decision-making, opportunity cost, market structures, and equilibrium analysis. These concepts are foundational for understanding microeconomic theory and applications.