Microeconomics Exam Study Guide: Key Concepts and Applications

Chapter 1: Introduction to Economics, Micro vs Macro, Opportunity Cost, Command vs Market Economy, The Methodology of Economics

Overview of Economics

Economics studies how individuals and societies allocate scarce resources to satisfy unlimited wants. It is divided into microeconomics (individual markets and agents) and macroeconomics (aggregate economy).

• Utility, Wants, Resources, and Scarcity: Utility refers to satisfaction gained from consuming goods/services. Scarcity means limited resources relative to unlimited wants, necessitating choices and trade-offs.

• Opportunity Cost: The value of the next best alternative forgone when making a choice. Explicit and implicit costs are both part of opportunity cost.

• Market vs Command Economy: Market economies allocate resources via prices and voluntary exchange; command economies rely on central planning.

• Positive vs Normative Economics: Positive statements describe facts; normative statements express opinions or what ought to be.

• Graphs and Relationships: Understanding direct (positive) and inverse (negative) relationships between variables, including straight-line and non-linear relationships.

Example: Choosing to attend college involves opportunity costs such as foregone income from working full-time.

Chapter 3: Supply and Demand

Market Model and Determinants

Supply and demand are fundamental concepts explaining how prices and quantities are determined in competitive markets.

• Perfectly Competitive Market: Many buyers and sellers, homogeneous products, free entry and exit.

• Law of Demand: As price decreases, quantity demanded increases (inverse relationship).

• Law of Supply: As price increases, quantity supplied increases (direct relationship).

• Marginal Utility: Additional satisfaction from consuming one more unit of a good.

• Shifts vs Movements: A shift in demand/supply curve is caused by non-price factors (income, tastes, prices of related goods, expectations, number of buyers/sellers). Movement along the curve is caused by price changes.

• Graphical Analysis: Know how to graph shortages (excess demand) and surpluses (excess supply), and how equilibrium is restored.

Example: An increase in consumer income shifts the demand curve for normal goods to the right.

Chapter 4: Market Efficiency, Price Ceilings and Price Floors, Consumer & Producer Surplus, Deadweight Loss

Surplus Concepts and Market Efficiency

Market efficiency occurs when total surplus (consumer + producer surplus) is maximized. Price controls can lead to inefficiencies.

• Consumer Surplus (CS): The difference between what consumers are willing to pay and what they actually pay. $CS = \text{Area below demand curve and above price}$

• Producer Surplus (PS): The difference between the price received and the minimum price producers are willing to accept. $PS = \text{Area above supply curve and below price}$

• Total Surplus: $TS = CS + PS$

• Deadweight Loss (DWL): Loss of total surplus due to market inefficiency (e.g., price controls). $DWL = \text{Area representing lost CS and PS}$

• Price Floor: Minimum legal price. Causes surplus if set above equilibrium price.

• Price Ceiling: Maximum legal price. Causes shortage if set below equilibrium price.

Example: Rent control (price ceiling) can cause housing shortages and deadweight loss.

Chapter 7: Elasticity

Elasticity Concepts and Types

Elasticity measures the responsiveness of one variable to changes in another, commonly price and quantity.

• Price Elasticity of Demand (Ed): Measures how much quantity demanded responds to price changes. $Ed = \frac{\% \text{ change in } Q_d}{\% \text{ change in } P}$

• Interpretation: $|Ed| > 1$ = elastic, $|Ed| < 1$ = inelastic, $|Ed| = 1$ = unit elastic.

• Types of Elasticity:

  • Demand: Price elasticity, cross-price elasticity (response to price changes of other goods), income elasticity (response to income changes).

  • Supply: Price elasticity of supply (response of quantity supplied to price changes).

• Determinants of Elasticity:

  • Availability of substitutes: More substitutes = more elastic demand.

  • Definition of market: Narrower definition = more elastic.

  • Necessities vs luxuries: Luxuries = more elastic.

  • Time horizon: Elasticity increases over time.

  • Budget share: Goods that take a larger share = more elastic.

Example: Demand for gasoline is inelastic in the short run but more elastic in the long run as consumers find alternatives.

HTML Table: Price Controls and Market Outcomes

The following table summarizes the effects of price ceilings and price floors on market outcomes:

Control Type	Binding Condition	Market Outcome	Surplus/Shortage	Deadweight Loss?
Price Ceiling	Set below equilibrium price	Quantity demanded > quantity supplied	Shortage	Yes
Price Floor	Set above equilibrium price	Quantity supplied > quantity demanded	Surplus	Yes

Additional info: The study guide also emphasizes graphical analysis and calculation skills for surplus and deadweight loss, as well as understanding the determinants and types of elasticity.