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Supply,Demand, and the Market Process Chapter 3. 1. Consumer Choice and the Law of Demand.

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Presentation on theme: "Supply,Demand, and the Market Process Chapter 3. 1. Consumer Choice and the Law of Demand."— Presentation transcript:

1 Supply,Demand, and the Market Process Chapter 3

2 1. Consumer Choice and the Law of Demand

3 Law of Demand n Law of Demand: There is an inverse relationship between the price of a good and the quantity consumers are willing to purchase. u As price of a good rises, consumers buy less. u The availability of substitutes --goods that do similar functions -- explains this negative relationship.

4 n A market demand schedule is a table that shows the quantity of a good people will demand at varying prices. Market Demand Schedule n Consider the market for cellular phones. A market demand schedule lays out the amount of cell phones that are demanded in the market for a spectrum of prices. n We can graph these points (price and the respective demand) to make a demand curve for cell phones.

5 Demand Market Demand Schedule Cell Phone Price (monthly bill) Millions of Cell Phone Subscribers $1232.1 $1073.5 $ 925.3 $ 797.6 $ 73 11.0 $ 63 16.0 $ 56 24.1 Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30

6 Demand Market Demand Schedule Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 Notice how the law of demand is reflected by the shape of the demand curve. As the price of a good rises …... consumers buy less.

7 Demand Market Demand Schedule Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 The height of the demand curve at any quantity shows the maximum price that consumers are willing to pay for that additional unit. Here, for the 11th unit...... consumers are only willing to pay up to $73 for it. While they would be willing to pay up to $92 for the 5.3 (millionth) unit.

8 Consumer Surplus n Consumer Surplus - the area below the demand curve but above the actual price paid. u Consumer surplus is the difference between the amount consumers are willing to pay and the amount they have to pay for a good. n Lower market prices will increase consumer surplus.

9 Consumer Surplus Lets consider the market for cellular phones again. This time we will assume that the demand for cell phones is more linear and that the market price is $100. Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 Demand If the market price is $100, then the 25th unit will not sell because those who demand it are only willing to pay $60 for cellular phone service. At $100, the 15th unit will sell because those who demand it are willing to pay up to $100 for cellular phone service. At $100, the 10th unit will sell because those who demand it are willing to pay up to $120 for cellular phone service. Market Price = $100 Price (monthly bill)

10 Consumer Surplus For all those goods under 15 units, people are willing to pay more than $100 for service. Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 Demand The area, represented by the distance above the actual price paid and below the demand curve, is called consumer surplus. This area represents the net gains to buyers from market exchange. Market Price = $100

11 Elastic and Inelastic Demand Curves n Elastic demand - quantity demanded is sensitive to small price changes. u Easy to substitute away from good. n Inelastic demand - quantity demanded is not sensitive to price changes. u Difficult to substitute away from good.

12 Elastic and Inelastic Demand Curves 2.00 1.25 2.00 1.25 Gasoli ne Tacos 1 2 3 45 6 7 8 9 10 1 2 3 45 6 7 8 9 If the market price for gasoline was to rise from $1.25 to $2.00, the quantity demanded in the market decreases insignificantly (from 8 to 7 units). If the market price for tacos rises from $1.25 to $2.00, the quantity demanded in the market decreases significantly (from 8 to 1 unit). Taco demand is highly sensitive to price changes and can be described as elastic; gasoline demand is relatively insensitive to price changes and can be described as inelastic.

13 2. Changes in Demand Versus Changes in Quantity Demanded

14 Changes in Demand and Quantity Demanded n Change in Demand - shift in entire demand curve. n Change in Quantity Demanded - movement along the same demand curve in response to a price change.

15 Change in Demand Price (dollars) Quantity (of Compact Disks per yr) 25 20 15 10 5 5 15 2025 30 If CDs cost $15 each, the CD demand curve D 1 shows that 10 units would be demanded. If, somehow, the preferences for CDs changed then the demand for CDs may change. Here we will assume that consumer income increases, increasing demand for CDs at all price levels. At $15 15 units are now demanded. If the price of CDs changed to $7.50, the quantity demanded for CDs would increase to 20 units. D1D1 D2D2 101520

16 Demand Curve Shifters n Change in the Number of Consumers n Change in Price of Related Good n Changes in Expectations n Demographic Changes n Changes in Consumer Tastes and Preferences n Changes in Consumer Income

17 1. Which of the following do you think would lead to an increase in the current demand for beef: (a) higher pork prices, (b) higher incomes, (c) higher prices of feed grains used to feed cows, (d) good weather conditions leading to a bumper (very good) corn crop, (e) an increase in the price of beef? Questions for Thought: 2. What is being held constant when a demand curve for a specific product (like shoes or apples, for example) is constructed? Explain why the demand curve for a product slopes downward and to the right.

18 3. Producer Choice and the Law of Supply

19 Producers n Opportunity Cost of Production - the sum of the producer’s cost of employing each resource required to produce the good. n Firms will not stay in business for long unless they are able to cover the cost of all resources employed, including the opportunity cost of those owned by the firm.

20 Role of Profits and Losses n Profit occurs when revenues are greater than cost. n Firms supplying goods for which consumers are willing to pay more than the opportunity cost of resources used will make a profit. n Firms making a profit will expand and those with a loss will contract.

21 Law of Supply n Law of Supply - there is a positive relationship between the price of a product and the amount of it that will be supplied. u As the price of a product rises, producers will be willing to supply more.

22 Supply Market Supply Schedule Cell Phone Price (monthly bill) Quantity of Cell Phones Supplied $ 605.0 $ 73 11.0 $ 80 15.1 $ 91 18.2 $107 21.0 $120 22.5 $135 24.1 Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30

23 Market Supply Schedule Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 Notice how the law of supply is reflected by the shape of the supply curve. As the price of a good rises …... producers supply more. Supply

24 Market Supply Schedule Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 The height of the supply curve at any quantity shows the minimum price necessary to induce producers to supply that next unit to market. Here, for the 11th unit...... producers require $73 to induce them to supply it. The height of the supply curve at any quantity also shows the opportunity cost of producing that next unit of the good. Supply

25 Producer Surplus Lets consider the market for cellular phones again. This time we will assume that the supply for cell phones is more linear and that the market price is $100. Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 If the market price is $100, then the 25th unit will not be produced because the cost of supplying it exceeds the market price of $140. At $100, the 15th unit will be produced because those who supply it are willing to do so for for at least $100. At $100, the 10th unit will be produced because those who supply it are willing to do so for at least $80. Market Price = $100 Price (monthly bill) Supply

26 Producer Surplus For market outputs of less then 15 units, producers are willing to supply the good for $100. Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 The area represented by the distance above the supply curve but below the actual sales price is called producer surplus. This area is the difference between the minimum amount required to induce producers to supply a good and the amount they actually receive. Market Price = $100

27 Elastic and Inelastic Supply Curves n Elastic supply- quantity supplied is sensitive to small price changes. n Inelastic supply - quantity supplied is not sensitive to price changes.

28 Elastic and Inelastic Supply Curves 2.00 1.25 2.00 1.25 1 2 3 45 6 7 8 9 10 1 2 3 45 6 7 8 9 If the market price for motor oil was to rise from $1.25 to $2.00, the quantity supplied in the market increases insignificantly (from 7 to 8 units). If the market price for burgers rises from $1.25 to $2.00, the quantity supplied in the market increases substantially (from 1 to 8 units). Burger supply is highly sensitive to price changes and can be described as elastic; motor oil supply is relatively insensitive to price changes and can be described as inelastic.

29 Short Run and Long Run n Short Run - Firms don’t have enough time to change plant size. u Supply tends to be inelastic in the short run. n Long Run - Firms have enough time to change plant size. u Supply tends to be much more elastic in the long run.

30 4. Changes in Supply Versus Changes in Quantity Supplied

31 Changes in Supply and Quantity Supplied n Change in Supply - shift in entire supply curve. n Change in Quantity Supplied - movement along the same supply curve in response to a price change.

32 Change in Supply Price (dollars) Quantity (Millions of Gal of Gas) 2.50 2.00 1.50 1.00.50 5 1015 2025 30 If the market price for gas is $1.50 a gallon, the gasoline supply curve S 1 shows that 20 units would be supplied. If, somehow, the opportunity costs for gas manufacturers changed then the supply of gas may change. Here we will assume that the cost of crude oil (an input in gasoline) increases, decreasing the supply of gas at all price levels. Now at $1.50, 15 units of gasoline are supplied. If the market price of gas changed to $.75, the quantity supplied of gasoline would decrease to 10 units. S1S1 101520 The Market for Gasoline S2S2

33 Supply Curve Shifters n Changes in Resource Prices n Change in Technology n Elements of Nature and Political Disruptions n Changes in Taxes

34 What must a firm do in order to make profit? 2. Define consumer and producer surplus. What is meant by economic efficiency and how does it relate to consumer and producer surplus? Questions for Thought: 1. What are profits and losses?

35 5. How Market Prices are Determined

36 Market Equilibrium 350400 450500550600650 7 8 9 10 11 12 13 > Excess Supply Downward This table and graph indicate the demand and supply conditions for oversized playing cards. Equilibrium will occur where the quantity demanded equals the quantity supplied. If the price in the market exceeds the equilibrium level, market forces will guide it to equilibrium. A price of $12 in this market will result in... resulting in excess supply. quantity supplied of 600... With an excess supply present, there will be downward pressure on price to clear the market. Demand Supply Quantity Demanded = 450 Quantity Supplied = 600 quantity demanded of 450 and

37 Market Equilibrium 350400 450500550600650 7 8 9 10 11 12 13 > Excess Supply Downward A price of $8 in this market will result in... resulting in excess demand. quantity demanded of 650... With an excess demand present, there will be upward pressure on price to clear the market. Demand Supply Quantity Demanded = 650 Quantity Supplied = 500 quantity supplied of 500 and < Excess Demand Upward

38 Market Equilibrium 350400 450500550600650 7 8 9 10 11 12 13 > Excess Supply Downward Demand Supply Quantity Demanded = 550 Quantity Supplied = 550 = < Balance Equilibrium Excess Demand Upward A price of $10 in this market will result in... resulting in a balance. quantity demanded of 550... With a balance present, there will be an equilibrium and the market will clear. quantity supplied of 550 and

39 Market Equilibrium 350400 450500550600650 7 8 9 10 11 12 13 > = < Excess Supply Downward Balance Equilibrium Excess Demand Upward At every price above market equilibrium there is excess supply and there will be downward pressure on the price level. At every price below market equilibrium there is excess demand and there will be upward pressure on the price level. It is at equilibrium that prices will rest. Demand Supply excess supply excess demand Equilibrium Price

40 Net Gains to Buyers and Sellers Returning to the market for cell phones, if the market price is driven to equilibrium through market pressures to exist where supply equals demand, then the market equilibrium in the cell phone market should be driven to $100 per month. Price (monthly bill) Quantity (of Cell Phone Subscribers) 140 120 100 80 60 5 1015 2025 30 Demand If the area above the market price and below the demand curve is called consumer surplus...... and the area above the supply curve but below the market price is called producer surplus...... Then the combined area represented in the graph to the right represents the net gains to buyers and sellers. It is here that all potential gains from production and exchange are realized. Supply Market Equilibrium Price = $100

41 6. How Markets Respond to Changes in Supply and Demand

42 Effects of a Change in Demand n If Demand decreases, the equilibrium price and quantity will fall. n If Demand increases, the equilibrium price and quantity will rise.

43 Consider the market for eggs. Price ($ per doz) Quantity (million doz eggs per week) 1.40 1.20 1.00.80.60 Q1Q1 Demand 1 Prior to Easter season, the market for eggs produces an equilibrium where Supply equals Demand 1 at a market price of $.80 and output of Q 1. Supply Demand 2 Q2Q2 When the Easter season arrives, the demand by consumers for eggs increases from Demand 1 to Demand 2. What happens to the equilibrium price and output level? At $.80 a dozen the quantity demanded exceeds the quantity supplied. There is upward pressure on price inducing the existing suppliers to increase their quantity supplied to Q 2, pushing the equilibrium price up to $1.00. What happens to equilibrium price and output after the Easter season? Market Adjustment to an Increase in Demand `

44 Effects of a Change in Supply n If Supply decreases, the equilibrium price will rise and the equilibrium quantity will fall. n If Supply increases, the equilibrium price will fall and the equilibrium quantity will rise.

45 Consider the market for romaine lettuce. Price ($ per head) 2.40 2.20 2.00 1.80 1.60 Q1Q1 Demand 1 Prior to a season of adverse weather affecting the yield of the market, an equilibrium exists where Supply equals Demand 1 with a market price of $1.80 and output of Q 1. Q2Q2 When the season of adverse weather arrives the supply of romaine lettuce falls, decreasing the supply from supply 1 to supply 2. What happens to the equilibrium price and output level? At $1.80 a head the quantity demanded exceeds the quantity supplied. There is upward pressure on price inducing the existing consumers to decrease their quantity demanded to Q 2, drawing up the equilibrium price to $2.00. What happens to equilibrium price and output when the weather returns to normal? Market Adjustment to a Decrease in Supply Supply 2 Supply 1 ` Quantity (million heads lettuce per week)

46 7. Time and the Adjustment Process

47 Time and the Adjustment Process n With the passage of time, the market adjustments of both producers and consumers will be more complete. u Both demand and supply are more elastic in the long run than in the short run.

48 Consider the market for laptop computers. Price Quantity P1P1 Q1Q1 Demand 1 We begin in the short run in equilibrium at output level Q 1 and price level P 1. Q2Q2 When the demand for laptops unexpectedly increases from demand 1 to demand 2, suppliers do there best to increase product in the market, pushing the price level upward to P 2. What happens to the equilibrium price and output in the long run, after suppliers have a chance to change their capacity? With time suppliers expand output pivoting the supply curve to its long run representation. The new equilibrium is where demand equals supply. The result, a further increase in equilibrium output, to Q 3, and a reduction in the equilibrium price to P 3. Time and Adjustment to Increase in Demand Supply SR Supply LR Demand 2 ` Q3Q3 P3P3 P2P2

49 8. Invisible Hand Principle

50 Invisible Hand n Invisible hand- the tendency of market prices to direct individuals pursuing their own interest into productive activities that also promote the economic well-being of society.

51 Communicating Information n Product prices communicate up-to- date information about the consumers’ valuation of additional units of each commodity. n Without the information provided by market price it would be impossible for decision-makers to determine how intensely a good was desired relative to its opportunity cost.

52 n Price changes bring the decisions of buyers and sellers into harmony. Coordinating Actions of Market Participants n Price changes create profits and losses which change production levels for various products.

53 Prices and Market Order n Market order is the result of market prices, not central planning.

54 n The efficiency of market organization is dependent upon: Qualifications u The presence of competitive markets. u Well-defined and enforced private property rights.

55 1. A drought during the summer of 1988 sharply reduced the 1988 output of wheat, corn, soybeans, and hay. Indicate the expected impact of the drought on the following: a. Prices of feed grains and hay during the summer of ‘88. b. Price of cattle during the fall of ‘88. (Hint: What has happened to the opportunity cost of maintaining cattle during the upcoming winter?) c. Price of cattle during the summer and fall of ‘89. Questions for Thought: 2. What is the “invisible hand” principle? Does it indicate that “good intentions” are necessary if one’s actions are going to be beneficial to others?

56 End Chapter 3


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