This document discusses demand, supply, and market equilibrium. It defines demand as the quantity of a good consumers are willing to purchase at different prices. Supply is defined as the quantity producers are willing to provide at different prices. The law of demand and supply state that demand is negatively related to price and supply is positively related to price. Market equilibrium occurs where quantity demanded equals quantity supplied at the market clearing price. The document provides examples of how equilibrium price and quantity change when demand or supply shifts.
2. Demand
• Quantity of a good or service that buyer will purchase at
every possible price
• Demand Curve shows the amount of a good that
consumers are willing to buy at each possible price during
a given time period, holding other things constant.
• Demand for a good or a service is determined by the
willingness and ability to pay for that good or service at a
given point of time.
3. Willingness to pay
Utility (Benefit) : total satisfaction received from consuming
a good or service
Utility depends on a consumer’s Tastes & Preferences
Everything else remaining same, if WTP Demand
Marketing strategies are designed to WTP
4. Ability to pay
Ability to consume depends on:
• Price of the good
• Income
• Price of other related goods
Everything else remaining same:
If Ability Demand
5. Law of demand
The law of demand states that, ceteris paribus or other
things being equal, the quantity demanded of a good
increases when its price decreases.
Qd= f(P, T, M, P’)
Quantity demanded varies inversely with price.
Demand curve slopes downward.
Substitution effect and income effect.
7. Quantity Demanded, Demand, Market Demand
• “My demand for apples is five kilograms”
• Five kilograms is the quantity demanded at a certain price
instead of demand. Demand refers to the entire demand
schedule or demand curve for the individual, not any
specific quantity.
• Change in quantity demanded refers to movement along
the demand curve when own price changes, while change
in demand refers to shift of the demand curve when other
factors change.
• Market Demand: sum of individual demands of all
consumers in the market. We will generally refer to market
demand when we talk about demand.
8. Factors that shift the demand curve
• Changes in consumer income:
Normal good: Demand increases as income increases.
Inferior good: Demand decreases as income increases.
• Changes in the price of related goods:
Substitutes: Goods that can serve as alternatives to a
given good.
Complements: Goods that are used in conjunction with
each other.
• Changes in tastes and preferences
• Changes in consumer expectation
• Changes in the number or composition of consumers
9. Supply
• Quantity of a good or service that producer will sell at
every possible price
• Supply Curve shows the amount of a good that producers
are willing to offer for sale at each possible price during a
given time period, holding other things constant.
• Supply for a good or a service is determined by the
willingness and ability to offer for sale that good or service
at a given point of time.
10. Willingness and Ability to sell
• As price rises, producers are willing to offer more for sale.
• As price rises, willingness to sell increases because it
becomes more profitable to produce the given good than
other uses of the resources available.
• As price rises, ability to sell also increases because the
higher price covers the higher marginal cost that results
from producing more output.
11. Law of supply
The law of supply states that, ceteris paribus or other
things being equal, the quantity supplied of a good
increases when its price increases.
Qs= f(P, T, R, P’)
Quantity supplied varies directly with price.
Supply curve is upward-sloping.
13. Quantity Supplied, Supply, Market Supply
• Quantity supplied refers to at a particular amount offered
for sale at a particular price as reflected by a point on the
given supply curve.
• Supply refers to the entire supply schedule or supply
curve for the individual, not any specific quantity.
• Change in quantity supplied refers to movement along the
supply curve when own price changes, while change in
supply refers to shift of the supply curve when other
factors change.
• Market Supply: sum of individual supplies of all producers
in the market. We will generally refer to market supply
when we talk about supply.
14. Factors that shift the supply curve
• Changes in technology
• Changes in the price of resources/inputs
• Changes in the price of alternative goods
• Changes in producer expectation
• Changes in the number of producers
• Changes in government regulations
16. Equilibrium Price and Quantity
At price P*, the quantity demanded is equal to the quantity
supplied.
P S
P*
D
Q* Q
17. If price is too high…
This results in excess supply or surplus for the
good equal to 24-14=10 thousand kgs
P
120 S
90
D
14 20 24 Q
18. If price is too low…
This results in excess demand or shortage for the
good equal to 12-2=10
P
S
90
60
D
16 20 26 Q
19. Inverse Demand Function
• Price as a function of quantity demanded.
• Example:
Demand Function
Qx = 50 – 2Px
Inverse Demand Function:
2Px = 50 – Qx
Px = 25 – 0.5Qx
20. Inverse Supply Function
• Price as a function of quantity supplied.
• Example:
Supply Function
• Qx = 10 + 2Px
Inverse Supply Function:
• Px = -5 + 0.5Qx
21. Market Equilibrium
• Find the price that clears the market
Qs = Qd
• Steady-state: When the market is in equilibrium, the
quantity demanded is the same as the quantity supplied
for the prevailing market price.
• This price at which demand is equal to supply is called
market clearing price.
22. Comparative Static Analysis
• Comparative static analysis examines how a change in an
exogenous variable will affect the level of an endogenous
variable in the model.
• Use this graphical tool to show how the equilibrium price
and quantity will change when a determinant of supply or
demand changes.
23. Demand Shift
• There is an increase in the price of pears due to an attack
by locusts.
• What would happen to the apple market?
♦Demand increases
• What happens to the equilibrium price and quantity?
25. Supply Shift
• The benign weather brought a bumper crop.
• What would happen to the market?
♦ Supply increases
• What happens to the equilibrium price and quantity?
27. Simultaneous Shifts in Demand and Supply
• Managers may encounter events that lead to
simultaneous shifts in both demand and supply.
• A tragic example:
♦In late 1990s, an earthquake hit Kobe, Japan.
♦The earthquake damaged Japan’s sake wine industry.
♦People drank to relieve the stress caused by the
earthquake.
• What happened to the market?
28. Demand Increase and Supply Decrease
Equilibrium is at a higher price but effect on quantity is uncertain.
P S’
S
P2
P1
D D’
Q1 Q