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Economics 2420. Chapter 3 Where Prices Come From: The Interaction of Demand and Supply. A. An Overview. Demand and supply are the two sides of the market for goods and services (factors of production also).
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Economics 2420 Chapter 3 Where Prices Come From:The Interaction of Demand and Supply
A. An Overview • Demand and supply are the two sides of the market for goods and services (factors of production also). • Demand and Supply are important because their interaction determines the prices of goods and services • Typically, demand reflects consumers’ behavior while supply reflects the producers’ behavior
B. The Demand Side of the Market • Quantity demanded - The quantity of a good or service that a consumer is willing to purchase at a given price.
Demand Curve for Printers Price($) 175 150 125 100 D-curve 75 0 Q 3 4 5 6 7
Demand Schedule and Demand Curve • Notice that both the demand schedule (table) and curve (graph) show that the relationship between the price and quantity demanded. • What is the nature of the relationship? Inverse.
The Law of Demand • 2.The Law of Demanda.The Law of Demand shows an inverse price-quantity relationship i.e. as price decreases, qt demanded increases, and vice-versa, holding everything else constant • 3. What are the justifications of the Law of Demand?Substitution effectThe change in the quantity demanded of a good that results from a change in price making the good more or less expensive relative to other goods that are substitutes.Income effect The change in the quantity demanded of a good that results from the effect of a change in the good’s price on consumer purchasing power. Law of Diminishing Marginal Utility(wait until chapter 10 in the text)
4. Some Exceptions to the Law of Demand • The giffen-good case- As price increases, the quantity demanded increases (Potatoes in Ireland; rice in China) • Bandwagon effect- People buy expensive goods to be like others- Air Nike Shoes • The snob effect- conspicuous consumption-expensive car to stand out from the crowd
5. Change in Quantity Demanded vs Change in Demand • ΔQ demanded- refers to a movement along the same demand curve due a price change only • Δ in Demand refers to the shift in the whole demand curve due to other factors than the price of the good
Change in Qty Demanded vs Change in Demand Movement from A to C is change in Qt demanded A shift in D-curve from D0 to D1 or D2 is change in demand Price A B C D1 D0 D2 Q
6. Shifters (Determinants) of Demand • ΔPrice of related goods • Substitutes Goods and services that can be used for the same purpose. P Coke D pepsi • Complements Goods that are used together. P camera rises=> Q films sold will decrease • ΔIncome • Normal good A good for which the demand increases as income rises and decreases as income falls (New Car). • Inferior good A good for which the demand increases as income falls, and decreases as income rises (Used car). • ΔTastes (smoking and lung cancer; mad cow disease and demand for beef) • ΔPopulation and demographics (demand for housing and school as population increases • DemographicsThe characteristics of a population with respect to age, race, and gender. • Δ Expected future prices( current demand increases if prices are expected to rise in the future)
Change in Qty Demanded vs Change in Demand Movement from A to C is change in Qt demanded A shift in D-curve from D0 to D1 or D2 is change in demand Price A B C D1 D0 D2 Q
C. The Supply Side of the Market 8. Quantity supplied The quantity of a good or service that a firm is willing to supply at a given price. Supply schedule A table that shows the relationship between the price of a product and the quantity of the product supplied. Supply curve A curve that shows the relationship between the price of a product and the quantity of the product demanded.
3- 6 Hewlett-Packard’s SupplySchedule and Supply Curve The Supply Side of the Market S-Curve Price 175 100 75 10 8 8.5
The Supply Side of the Market 9. Law of supply shows a positive price- quantity relationship, i.e. as price increases, qt supplied increases and vice- versa
10. ΔQt Supplied and vs Δ in Supply • ΔQt Supplied refers to a movement along the same supply curve due to a change in product price • Δ in Supply refers to a shift in the whole supply curve due to factors other than the product price
11. Variables That Shift Supply • Δ in Price of inputs (labor cost, capital cost, etc.) • Δ in Technology • Improvement in technology reduces and increases supply (positive) and lack of it will increase cost and reduce supply (negative) • Δ in Prices of substitutes in production • Δ Expected future prices • Δ Number of firms in the market
Shifts in Supply • Price S2 S0 S1 Increase Decrease
Market Equilibrium: Putting Demand and Supply Together • 12. Market equilibrium price -A situation where quantity demanded equals quantity supplied. • Competitive market equilibrium A market equilibrium with many buyers and many sellers.
The Effect of Surpluses and Shortages on the Market Price Market Equilibrium: Putting Demand and Supply Together Price S Surplus 125 Pe=100 75 D D Q 18.5 21.5 19.5 Qe
Price above and below Eq. • 13a. Surplus A situation in which the quantity supplied is greater than the quantity demanded. • 13b. Shortage A situation in which the quantity demanded is greater than the quantity supplied.
How does the market eliminate surpluses and shortages? • When price is set above the market eq. price, a surplus will occur; but it will be eliminated because competition will force sellers to accept lower and lower prices • When price is set below the market eq. price, a shortage will occur; but it will be eliminated because competition will force buyers higher and higher prices up the eq. price • At equilibrium, there are no surpluses, nor shortages!
Market Equilibrium • 14. The market equilibrium price does not tell us anything about fairness. It only tells us that who ever can pay the price will be get the Qe. • 15. The market equilibrium price is important because it channels resources to their best use. • When consumers buy a good or service they channel resources to the production of that good or service • Price of DVD Production of DVDs by hiring workers, investing machines to make DVDs, etc.
16. The Effect of Demand and Supply Shifts on Equilibrium • If demand increases and supply remains constant, then both eq. price and quantity will increase. Illustrate. • If supply increases (deceases) and demand remains the same, then eq. decreases (increases) and eq. qt increases (decreases). Illustrate. • If both demand and supply increase, then we cannot predict what happens to the eq. price. It depends on the price elasticity of demand and supply. Illustrate.