Microeconomics: Demand, Supply, and Market Equilibrium Study Guide

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Demand and Quantity Demanded

Understanding Demand Shifts vs. Movements Along the Demand Curve

In microeconomics, it is crucial to distinguish between a change in demand and a change in quantity demanded. These concepts are foundational for analyzing market behavior.

Change in Demand: Represented by a shift of the entire demand curve (leftward or rightward), indicating that consumers are willing to buy more or less of a good at every price due to factors other than price (e.g., income, tastes, prices of related goods).
Change in Quantity Demanded: Represented by a movement along a given demand curve, caused solely by a change in the good's own price.
Example: If consumer incomes rise, the demand curve for normal goods shifts rightward; if the price of the good falls, quantity demanded increases along the same curve.

Types of Goods: Complements, Substitutes, Normal, and Inferior Goods

Classifying Goods Based on Consumer Response to Income and Price Changes

Goods are categorized based on how demand responds to changes in income and the prices of related goods.

Complement: A good whose demand increases when the demand for another good increases (e.g., mac and cheese).
Substitute: A good whose demand increases when the price of another good increases.
Normal Good: Demand increases as consumer income rises.
Inferior Good: Demand decreases as consumer income rises (e.g., sardines, if considered inferior).
Example: If a decrease in income leads to increased demand for sardines, sardines are an inferior good.

Supply and Quantity Supplied

Understanding Supply Shifts vs. Movements Along the Supply Curve

Like demand, supply can shift or move along the curve, depending on the underlying cause.

Change in Supply: A shift of the supply curve (leftward or rightward), caused by factors such as input prices, technology, or number of sellers.
Change in Quantity Supplied: A movement along the supply curve, caused by a change in the good's own price.
Example: If the cost of producing peaches rises, the supply curve shifts left; if the price of peaches rises, quantity supplied increases along the curve.

Supply Schedules and Curves

Tabular and Graphical Representation of Supply

Supply can be represented in tables (supply schedules) or graphs (supply curves).

Supply Schedule: A table showing the relationship between price and quantity supplied.
Supply Curve: A graph showing the relationship between price and quantity supplied, typically upward sloping.
Example Table:

Price ($)	Quantity Supplied
10	100
20	200
30	300

Market Equilibrium

Equilibrium Price and Quantity

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

Equilibrium Price (): The price at which .
Shortage: Occurs when market price is below equilibrium, .
Surplus: Occurs when market price is above equilibrium, .
Example Equation:

Factors Causing Shifts in Demand and Supply

Determinants of Demand and Supply Shifts

Various factors can shift the demand or supply curve, affecting market outcomes.

Demand Shifters: Income, tastes, prices of related goods, expectations, population.
Supply Shifters: Input prices, technology, number of sellers, expectations, government policies.
Example: An embargo on Swedish products shifts the supply curve for Swedish furniture in the U.S. to the left.

Law of Supply

Relationship Between Price and Quantity Supplied

The law of supply states that, ceteris paribus, an increase in price leads to an increase in quantity supplied, and a decrease in price leads to a decrease in quantity supplied.

Law of Supply Equation:

Example: If the price of lumber rises, suppliers are willing to supply more lumber.

Applications and Market Scenarios

Analyzing Real-World Market Changes

Microeconomic principles are applied to understand market changes due to external events or policy interventions.

Wildfires: Destruction of resources shifts the supply curve for lumber to the left.
Pandemic Effects: Restrictions on face-to-face classes increase demand for online classes, shifting the demand curve rightward.
Government Restrictions: Limiting logging decreases supply, shifting the supply curve left and increasing price.

Summary Table: Demand vs. Quantity Demanded and Supply vs. Quantity Supplied

Concept	Definition	Graphical Representation
Change in Demand	Consumers buy more/less at every price	Shift of demand curve
Change in Quantity Demanded	Consumers buy more/less due to price change	Movement along demand curve
Change in Supply	Producers supply more/less at every price	Shift of supply curve
Change in Quantity Supplied	Producers supply more/less due to price change	Movement along supply curve

Key Formulas

Equilibrium Condition:

Law of Supply:

Law of Demand:

Additional info:

Some examples and definitions have been expanded for clarity and completeness.
Tables have been recreated to illustrate supply schedules and conceptual comparisons.