Introduction to Demand and Supply

Demand and Supply Overview

Introduction to Demand

  • Focus on understanding the concepts of demand and supply, and market equilibrium.

  • Differentiate between quantity demanded versus demand.

  • Clarification that quantity supplied differs from supply.

Definitions

Quantity Demanded vs. Demand

  • Quantity Demanded:

    • Definition: The amount that a consumer is willing and able to buy at a given price.

    • Example: Graph representation clarifies its specific context.

  • Demand:

    • Definition: The demand schedule or demand curve showing the relationship between various prices and quantities demanded.

    • It reflects shifts in demand based on various influences, unlike quantity demanded, which refers to specific points on the demand curve.

Law of Demand

  • Definition: The law describes the negative relationship between price and quantity demanded.

    • If price decreases, quantity demanded increases.

    • If price increases, quantity demanded decreases.

    • Visual representation: Price and quantity demanded move in opposite directions.

Demand Schedule and Graph

  • Demand Schedule:

    • Example data:

    • Price: [5, 4, 3, 2, 1]

    • Quantity Demanded (QD): [10, 20, 35, 55, 80]

    • Understanding the coordinates and how to plot them on a graph leads to the creation of the demand curve.

  • Graphing Demand:

    • Demonstrates how different price points correlate to quantities demanded.

    • Each point on the demand curve relates to a quantity demanded at a specific price, outlining that quantity demanded is merely a point on the broader demand curve.

Changes in Demand

  • Determinants of Demand: Factors influencing buying decisions; changes in any of these will shift the demand curve.

  • Factors:

    1. Income:

    • Normal Goods: Demand rises as income rises (curve shifts right).

    • Inferior Goods: Demand falls as income rises (curve shifts left).

    • Example: Ramen noodles (inferior good).

    1. Price of Related Goods:

    • Substitutes: If the price of Coke increases, demand for Pepsi increases.

    • Complements: If the price of computers increases, demand for software decreases.

    1. Consumer Expectations:

    • Expected future price changes affect current demand (e.g., expected price increases lead to higher current demand).

    1. Tastes and Preferences: Changes in consumer preferences can shift demand.

    2. Number of Buyers: An increase in the number of consumers raises demand, shifting the curve right.

Changes in Quantity Demanded

  • Demonstrated via a shift along the demand curve caused solely by price changes.

  • Graphical Example illustrates moving from point A to point B due to a price drop from $5 to $4.

Overview of Supply

  • Quantity Supplied vs. Supply:

    • Quantity Supplied: The amount a seller is willing to sell at a given price.

    • Supply: The entire supply schedule or curve showing the relationship between prices and quantities supplied.

Law of Supply

  • Definition: Describes a direct relationship between price and quantity supplied.

    • If price increases, quantity supplied increases.

    • If price decreases, quantity supplied decreases.

Changes in Supply

  • Determinants of Supply: Factors influencing selling plans; changes shift the supply curve.

  • Factors:

    1. Input Prices: Higher costs lead to lower supplies; an example is ice cream production costs.

    2. Price of Other Goods: Substitution in production where producing one good affects another's supply (e.g., shirts versus pants).

    3. Producer Expectations: Higher anticipated future prices lead to withholding supplies now.

    4. Technology: Advances usually lead to increased supply.

    5. Number of Sellers: Increased sellers lead to increased supply.

Changes in Quantity Supplied

  • Demonstrated through movements along the supply curve due to price changes, contrasting with shifts in the curve itself, caused by the outlined determinants.

Market Equilibrium

  • Illustrates the intersection of supply and demand curves representing equilibrium price and quantity.

  • Changes in either demand or supply shift the equilibrium price and quantity.

  • Surpluses and Shortages:

    • Surplus: When quantity supplied exceeds quantity demanded at a specific price.

    • Shortage: When quantity demanded exceeds quantity supplied at a specific price.

Simultaneous Changes in Demand and Supply

  • Increase in Demand and Decrease in Supply: Price decreases, quantity unknown.

  • Decrease in Demand and Increase in Supply: Price decreases, quantity unknown.

  • Increase in both Demand and Supply: Quantity increases, price unclear.

  • Decrease in both Demand and Supply: Quantity decreases, price unclear.

Conclusion

  • Reiteration of the core concepts regarding demand and supply, the significance of understanding the differences between quantity demanded/supplied and the overall demand/supply.

  • Understanding market equilibrium ensures awareness of how economic forces interact in determining prices and quantities.

  • Final thoughts underscore the complexity and interconnectivity of these market elements that define economic interactions.