Title: Theory of demand

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Title Theory of demand

• Subject Economics
• Author Lai Yuen Ki, Anita
• Target audience Secondary 4 students
• How the presentation is to be used lecture

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Name Lai Yuen Ki, Anita Student number
98059120 Course EDD 5161F
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Theory of Demand
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Quantity demanded

• The quantity of a good a person is willing and
  able to buy at a particular price in a period of
  time

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Who eats more?
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Factors affecting quantity demanded
Qd
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The Law of Demand

• Within a period of time, an increase (decrease)
  in price of a good results in a decrease
  (increase) in its quantity demanded, ceteris
  paribus.

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The Law of Demand
Price
P1
P2
Quantity
Q1
Q2
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The Law of Demand
Price
P1
P2
Quantity
Q1
Q2
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The Law of Demand
Price
P1
P2
Quantity
Q1
Q2
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The Law of Demand
Price
P1
P2
Quantity
Q1
Q2
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Ceteris paribus
Other factors being constant
Qd
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The Law of Demand
Price of the good
Qd
Ceteris paribus
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Is change in Qd the same as change in demand?
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Change in quantity demanded

• Caused by a change in a goods price
• Holding all other factors constant
• A movement along the same demand curve

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Change in quantity demanded
Price
P1
P2
Quantity
Q1
Q2
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Change in quantity demanded
Price
P1
P2
Quantity
Q1
Q2
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Change in quantity demanded
Price
P1
P2
Quantity
Q1
Q2
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Change in demand

• Caused by a change in factors (e.g. income, taste
  etc) other than a goods own price
• A shift of the entire demand curve

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Change in demand
Price
P1
P2
Q1
Q2
Quantity
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Revision

• What is the law of demand?
• What is the change in quantity demanded?
• What is the change in demand?