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Understanding Demand What is the law of demand?

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1 Understanding Demand What is the law of demand?
How do the substitution effect and income effect influence decisions? What is a demand schedule? What is a demand curve?

2 What Is the Law of Demand?
The law of demand states that consumers buy more of a good when its price decreases and less when its price increases. The law of demand is the result of two separate behavior patterns that overlap, the substitution effect and the income effect. These two effects describe different ways that a consumer can change his or her spending patterns for other goods.

3 The Substitution Effect and Income Effect
The substitution effect occurs when consumers react to an increase in a good’s price by consuming less of that good and more of other goods. The Income Effect The income effect happens when a person changes his or her consumption of goods and services as a result of a change in real income.

4 Individual Demand Schedule Market Demand Schedule
The Demand Schedule A demand schedule is a table that lists the quantity of a good a person will buy at each different price. A market demand schedule is a table that lists the quantity of a good all consumers in a market will buy at each different price. Demand Schedules Individual Demand Schedule Price of a slice of pizza Quantity demanded per day Market Demand Schedule Price of a slice of pizza Quantity demanded per day $.50 $1.00 $1.50 $2.00 $2.50 $3.00 5 4 3 2 1 $.50 $1.00 $1.50 $2.00 $2.50 $3.00 300 250 200 150 100 50

5 Price per slice (in dollars)
The Demand Curve Market Demand Curve 3.00 2.50 2.00 1.50 1.00 .50 50 100 150 200 250 300 350 Slices of pizza per day Price per slice (in dollars) A demand curve is a graphical representation of a demand schedule. When reading a demand curve, assume all outside factors, such as income, are held constant. Demand

6 Section 1 Assessment 1. The law of demand states that (a) consumers will buy more when a price increases. (b) price will not influence demand. (c) consumers will buy less when a price decreases. (d) consumers will buy more when a price decreases. 2. If the price of a good rises and income stays the same, what is the effect on demand? (a) the prices of other goods drop (b) fewer goods are bought (c) more goods are bought (d) demand stays the same Want to connect to the PHSchool.com link for this section? Click Here!

7 Section 1 Assessment 1. The law of demand states that (a) consumers will buy more when a price increases. (b) price will not influence demand. (c) consumers will buy less when a price decreases. (d) consumers will buy more when a price decreases. 2. If the price of a good rises and income stays the same, what is the effect on demand? (a) the prices of other goods drop (b) fewer goods are bought (c) more goods are bought (d) demand stays the same Want to connect to the PHSchool.com link for this section? Click Here!

8 Shifts of the Demand Curve
What is the difference between a change in quantity demanded and a shift in the demand curve? What factors can cause shifts in the demand curve? How does the change in the price of one good affect the demand for a related good?

9 Shifts in Demand Ceteris paribus is a Latin phrase economists use meaning “all other things held constant.” A demand curve is accurate only as long as the ceteris paribus assumption is true. When the ceteris paribus assumption is dropped, movement no longer occurs along the demand curve. Rather, the entire demand curve shifts.

10 What Causes a Shift in Demand?
Several factors can lead to a change in demand: 1. Income Changes in consumers incomes affect demand. A normal good is a good that consumers demand more of when their incomes increase. An inferior good is a good that consumers demand less of when their income increases. 2. Consumer Expectations Whether or not we expect a good to increase or decrease in price in the future greatly affects our demand for that good today. 3. Population Changes in the size of the population also affects the demand for most products. 4. Consumer Tastes and Advertising Advertising plays an important role in many trends and therefore influences demand. – A change in demand at every price causes a shift in the demand curve.

11 Prices of Related Goods
The demand curve for one good can be affected by a change in the demand for another good. Complements are two goods that are bought and used together. Example: skis and ski boots Substitutes are goods used in place of one another. Example: skis and snowboards

12 Section 2 Assessment 1. Which of the following does not cause a shift of an entire demand curve? (a) a change in price (b) a change in income (c) a change in consumer expectations (d) a change in the size of the population 2. Which of the following statements is accurate? (a) When two goods are complementary, increased demand for one will cause decreased demand for the other. (b) When two goods are complementary, increased demand for one will cause increased demand for the other. (c) If two goods are substitutes, increased demand for one will cause increased demand for the other. (d) A drop in the price of one good will cause increased demand for its substitute. Want to connect to the PHSchool.com link for this section? Click Here!

13 Section 2 Assessment 1. Which of the following does not cause a shift of an entire demand curve? (a) a change in price (b) a change in income (c) a change in consumer expectations (d) a change in the size of the population 2. Which of the following statements is accurate? (a) When two goods are complementary, increased demand for one will cause decreased demand for the other. (b) When two goods are complementary, increased demand for one will cause increased demand for the other. (c) If two goods are substitutes, increased demand for one will cause increased demand for the other. (d) A drop in the price of one good will cause increased demand for its substitute. Want to connect to the PHSchool.com link for this section? Click Here!

14 Preview What is something you would still buy even if the price went up a little?

15 Elasticity of Demand What is elasticity of demand?
How can a demand schedule and demand curve be used to determine elasticity of demand? What factors affect elasticity? How do firms use elasticity and revenue to make decisions?

16 What Is Elasticity of Demand?
Elasticity of demand is a measure of how consumers react to a change in price. Demand for a good that consumers will continue to buy despite a price increase is inelastic. Demand for a good that is very sensitive to changes in price is elastic.

17 Calculating Elasticity
Elasticity of Demand Elasticity is determined using the following formula: Elasticity = Percentage change in quantity demanded Percentage change in price To find the percentage change in quantity demanded or price, use the following formula: subtract the new number from the original number, and divide the result by the original number. Ignore any negative signs, and multiply by 100 to convert this number to a percentage: Percentage change = Original number – New number Original number x 100

18 Elastic Demand If demand is elastic, a small change in price leads to a relatively large change in the quantity demanded. Follow this demand curve from left to right. Price Quantity $7 $6 $5 $4 $3 $2 $1 Elastic Demand 5 10 15 20 25 30 Demand The price decreases from $4 to $3, a decrease of 25 percent. $4 – $3 $4 x 100 = 25 The quantity demanded increases from 10 to 20. This is an increase of 100 percent. 10 – 20 10 x 100 = 100 Elasticity of demand is equal to 4.0. Elasticity is greater than 1, so demand is elastic. In this example, a small decrease in price caused a large increase in the quantity demanded. 100% 25% = 4.0

19 Inelastic Demand Inelastic Demand
Price Quantity $7 $6 $5 $4 $3 $2 $1 Inelastic Demand 5 10 15 20 25 30 Demand If demand is inelastic, consumers are not very responsive to changes in price. A decrease in price will lead to only a small change in quantity demanded, or perhaps no change at all. Follow this demand curve from left to right as the price decreases sharply from $6 to $2. The price decreases from $6 to $2, a decrease of about 67 percent. $6 – $2 $6 x 100 = 67 The quantity demanded increases from 10 to 15, an increase of 50 percent. 10 – 15 10 x 100 = 50 Elasticity of demand is about The elasticity is less than 1, so demand for this good is inelastic. The increase in quantity demanded is small compared to the decrease in price. 50% 67% = 0.75

20 Factors Affecting Elasticity
Several different factors can affect the elasticity of demand for a certain good. 1. Availability of Substitutes If there are few substitutes for a good, then demand will not likely decrease as price increases. The opposite is also usually true. 2. Relative Importance Another factor determining elasticity of demand is how much of your budget you spend on the good. 3. Necessities versus Luxuries Whether a person considers a good to be a necessity or a luxury has a great impact on the good’s elasticity of demand for that person. 4. Change over Time Demand sometimes becomes more elastic over time because people can eventually find substitutes.

21 Elasticity and Revenue
The elasticity of demand determines how a change in prices will affect a firm’s total revenue or income. A company’s total revenue is the total amount of money the company receives from selling its goods or services. Firms need to be aware of the elasticity of demand for the good or service they are providing. If a good has an elastic demand, raising prices may actually decrease the firm’s total revenue.

22 Section 3 Assessment 1. What does elasticity of demand measure? (a) an increase in the quantity available (b) a decrease in the quantity demanded (c) how much buyers will cut back or increase their demand when prices rise or fall (d) the amount of time consumers need to change their demand for a good 2. What effect does the availability of many substitute goods have on the elasticity of demand for a good? (a) demand is elastic (b) demand is inelastic (c) demand is unitary elastic (d) the availability of substitutes does not have an effect Want to connect to the PHSchool.com link for this section? Click Here!

23 Section 3 Assessment 1. What does elasticity of demand measure? (a) an increase in the quantity available (b) a decrease in the quantity demanded (c) how much buyers will cut back or increase their demand when prices rise or fall (d) the amount of time consumers need to change their demand for a good 2. What effect does the availability of many substitute goods have on the elasticity of demand for a good? (a) demand is elastic (b) demand is inelastic (c) demand is unitary elastic (d) the availability of substitutes does not have an effect Want to connect to the PHSchool.com link for this section? Click Here!

24 Preview If your favorite place to eat went up $50 a plate, how often would you go there?

25 Understanding Supply What is the law of supply?
What are supply schedules and supply curves? What is elasticity of supply? What factors affect elasticity of supply?

26 The Law of Supply According to the law of supply, suppliers will offer more of a good at a higher price. Price As price increases… Supply Quantity supplied increases Price As price falls… Supply Quantity supplied falls

27 How Does the Law of Supply Work?
Economists use the term quantity supplied to describe how much of a good is offered for sale at a specific price. The promise of increased revenues when prices are high encourages firms to produce more. Rising prices draw new firms into a market and add to the quantity supplied of a good.

28 Price per slice of pizza Slices supplied per day
Supply Schedules A market supply schedule is a chart that lists how much of a good all suppliers will offer at different prices. $.50 1,000 Price per slice of pizza Slices supplied per day Market Supply Schedule $1.00 1,500 $1.50 2,000 $2.00 2,500 $2.50 3,000 $3.00 3,500

29 Output (slices per day)
Supply Curves Market Supply Curve Price (in dollars) Output (slices per day) 3.00 2.50 2.00 1.50 1.00 .50 500 1000 1500 2000 2500 3000 3500 A market supply curve is a graph of the quantity supplied of a good by all suppliers at different prices. Supply

30 Elasticity of Supply Elasticity of supply is a measure of the way quantity supplied reacts to a change in price. If supply is not very responsive to changes in price, it is considered inelastic. An elastic supply is very sensitive to changes in price.

31 What Affects Elasticity of Supply?
Time In the short run, a firm cannot easily change its output level, so supply is inelastic. In the long run, firms are more flexible, so supply can become more elastic.

32 Section 1 Assessment 1. What is the law of supply? (a) the lower the price, the larger the quantity supplied (b) the higher the price, the larger the quantity supplied (c) the higher the price, the smaller the quantity supplied (d) the lower the price, the more manufacturers will produce the good 2. What happens when the price of a good with an elastic supply goes down? (a) existing producers will expand and some new producers will enter the market (b) some producers will produce less and others will drop out of the market (c) existing firms will continue their usual output but will earn less (d) new firms will enter the market as older ones drop out Want to connect to the PHSchool.com link for this section? Click Here!

33 Section 1 Assessment 1. What is the law of supply? (a) the lower the price, the larger the quantity supplied (b) the higher the price, the larger the quantity supplied (c) the higher the price, the smaller the quantity supplied (d) the lower the price, the more manufacturers will produce the good 2. What happens when the price of a good with an elastic supply goes down? (a) existing producers will expand and some new producers will enter the market (b) some producers will produce less and others will drop out of the market (c) existing firms will continue their usual output but will earn less (d) new firms will enter the market as older ones drop out Want to connect to the PHSchool.com link for this section? Click Here!

34 Preview If you were to create your own business, how would you make sure you made money?

35 Costs of Production How do firms decide how much labor to hire?
What are production costs? How do firms decide how much to produce?

36 A Firm’s Labor Decisions
Business owners have to consider how the number of workers they hire will affect their total production. The marginal product of labor is the change in output from hiring one additional unit of labor, or worker. Marginal Product of Labor Labor (number of workers) Output (beanbags per hour) Marginal product of labor 1 4 2 10 6 3 17 7 4 23 6 5 28 31 3 7 32 1 8 –1

37 Labor (number of workers) Marginal Product of labor
Marginal Returns Increasing, Diminishing, and Negative Marginal Returns Labor (number of workers) Marginal Product of labor (beanbags per hour) 8 7 6 5 4 3 2 1 –1 –2 –3 1 2 3 Increasing marginal returns Increasing marginal returns occur when marginal production levels increase with new investment. Diminishing marginal returns occur when marginal production levels decrease with new investment. 4 5 6 7 Diminishing marginal returns Negative marginal returns occur when the marginal product of labor becomes negative. 8 9 Negative marginal returns

38 Production Costs A fixed cost is a cost that does not change, regardless of how much of a good is produced. Examples: rent and salaries Variable costs are costs that rise or fall depending on how much is produced. Examples: costs of raw materials, some labor costs. The total cost equals fixed costs plus variable costs. The marginal cost is the cost of producing one more unit of a good.

39 Setting Output Marginal revenue is the additional income from selling one more unit of a good. It is usually equal to price. To determine the best level of output, firms determine the output level at which marginal revenue is equal to marginal cost. Production Costs Total revenue Profit (total revenue – total cost) Marginal revenue (market price) Marginal cost Total cost (fixed cost + variable cost) Variable cost Fixed cost Beanbags (per hour) $ –36 –20 21 40 1 2 3 4 $0 24 48 72 96 $24 $8 5 $36 44 51 56 8 12 15 20 36 57 72 84 93 5 6 7 8 120 144 168 192 24 9 12 15 63 99 27 36 48 98 92 79 216 240 264 288 24 19 30 37 36 9 10 11 12 82 106 136 173 118 142 172 209

40 Section 2 Assessment 1. What are diminishing marginal returns of labor? (a) some workers increase output but others have the opposite effect (b) additional workers increase total output but at a decreasing rate (c) only a few workers will have to wait their turn to be productive (d) additional workers will be more productive 2. How does a firm set its total output to maximize profit? (a) set production so that total revenue plus costs is greatest (b) set production at the point where marginal revenue is smallest (c) determine the largest gap between total revenue and total cost (d) determine where marginal revenue and profit are the same Want to connect to the PHSchool.com link for this section? Click Here!

41 Section 2 Assessment 1. What are diminishing marginal returns of labor? (a) some workers increase output but others have the opposite effect (b) additional workers increase total output but at a decreasing rate (c) only a few workers will have to wait their turn to be productive (d) additional workers will be more productive 2. How does a firm set its total output to maximize profit? (a) set production so that total revenue plus costs is greatest (b) set production at the point where marginal revenue is smallest (c) determine the largest gap between total revenue and total cost (d) determine where marginal revenue and profit are the same Want to connect to the PHSchool.com link for this section? Click Here!

42 Preview Imagine you own a company that makes baby dolls. If the cost of baby clothes increased, what would happen to the amount of baby dolls you would be willing to make?

43 How do input costs affect supply?
Changes in Supply How do input costs affect supply? How can the government affect the supply of a good? What other factors can influence supply?

44 Input Costs and Supply Any change in the cost of an input such as the raw materials, machinery, or labor used to produce a good, will affect supply. As input costs increase, the firm’s marginal costs also increase, decreasing profitability and supply. Input costs can also decrease. New technology can greatly decrease costs and increase supply.

45 Government Influences on Supply
By raising or lowering the cost of producing goods, the government can encourage or discourage an entrepreneur or industry. Subsidies A subsidy is a government payment that supports a business or market. Subsidies cause the supply of a good to increase. Taxes The government can reduce the supply of some goods by placing an excise tax on them. An excise tax is a tax on the production or sale of a good. Regulation Regulation occurs when the government steps into a market to affect the price, quantity, or quality of a good. Regulation usually raises costs.

46 Other Factors Influencing Supply
The Global Economy The supply of imported goods and services has an impact on the supply of the same goods and services here. Government import restrictions will cause a decrease in the supply of restricted goods. Future Expectations of Prices Expectations of higher prices will reduce supply now and increase supply later. Expectations of lower prices will have the opposite effect. Number of Suppliers If more firms enter a market, the market supply of the good will rise. If firms leave the market, supply will decrease.

47 Section 3 Assessment 1. What affect does a rise in the cost of raw materials have on the cost of a good? (a) A rise in the cost of raw materials lowers the overall cost of production. (b) The good becomes cheaper to produce. (c) The good becomes more expensive to produce. (d) This does not have any affect on the eventual price of a good. 2. When government actions cause the supply of a good to increase, what happens to the supply curve for that good? (a) It shifts to the left. (b) It shifts to the right. (c) It reverses direction. (d) The supply curve is unaffected. Want to connect to the PHSchool.com link for this section? Click Here!

48 Section 3 Assessment 1. What affect does a rise in the cost of raw materials have on the cost of a good? (a) A rise in the cost of raw materials lowers the overall cost of production. (b) The good becomes cheaper to produce. (c) The good becomes more expensive to produce. (d) This does not have any affect on the eventual price of a good. 2. When government actions cause the supply of a good to increase, what happens to the supply curve for that good? (a) It shifts to the left. (b) It shifts to the right. (c) It reverses direction. (d) The supply curve is unaffected. Want to connect to the PHSchool.com link for this section? Click Here!

49 Preview Tell me of a time when a large number of people wanted something but there was not enough.

50 Combining Supply and Demand
How do supply and demand create balance in the marketplace? What are differences between a market in equilibrium and a market in disequilibrium? What are the effects of price ceilings and price floors?

51 Price of a slice of pizza Combined Supply and Demand Schedule
Balancing the Market The point at which quantity demanded and quantity supplied come together is known as equilibrium. Price per slice Equilibrium Point Finding Equilibrium Price of a slice of pizza Quantity demanded Quantity supplied Result Combined Supply and Demand Schedule $ .50 300 100 $3.50 $3.00 $2.50 $2.00 $1.50 $1.00 $.50 Slices of pizza per day 50 150 200 250 350 Supply Demand $2.00 $2.50 $3.00 150 100 50 250 300 350 Surplus from excess supply $1.00 250 150 Shortage from excess demand $1.50 200 Equilibrium Equilibrium Price a Equilibrium Quantity

52 Market Disequilibrium
If the market price or quantity supplied is anywhere but at the equilibrium price, the market is in a state called disequilibrium. There are two causes for disequilibrium: Excess Demand Excess demand occurs when quantity demanded is more than quantity supplied. Excess Supply Excess supply occurs when quantity supplied exceeds quantity demanded. Interactions between buyers and sellers will always push the market back towards equilibrium.

53 Price Ceilings In some cases the government steps in to control prices. These interventions appear as price ceilings and price floors. A price ceiling is a maximum price that can be legally charged for a good. An example of a price ceiling is rent control, a situation where a government sets a maximum amount that can be charged for rent in an area.

54 Price Floors A price floor is a minimum price, set by the government, that must be paid for a good or service. One well-known price floor is the minimum wage, which sets a minimum price that an employer can pay a worker for an hour of labor.

55 Section 1 Assessment 1. Equilibrium in a market means which of the following? (a) the point at which quantity supplied and quantity demanded are the same (b) the point at which unsold goods begin to pile up (c) the point at which suppliers begin to reduce prices (d) the point at which prices fall below the cost of production 2. The government’s price floor on low wages is called the (a) market equilibrium (b) base wage rate (c) minimum wage (d) employment guarantee Want to connect to the PHSchool.com link for this section? Click Here!

56 Section 1 Assessment 1. Equilibrium in a market means which of the following? (a) the point at which quantity supplied and quantity demanded are the same (b) the point at which unsold goods begin to pile up (c) the point at which suppliers begin to reduce prices (d) the point at which prices fall below the cost of production 2. The government’s price floor on low wages is called the (a) market equilibrium (b) base wage rate (c) minimum wage (d) employment guarantee Want to connect to the PHSchool.com link for this section? Click Here!

57 Price of lawn mower Quantity Demanded Quantity Supplied $200 14,000 2,000 $250 12,000 3,000 $300 10,000 4,000 $350 8,000 5,000 $400 6,000 $450 7,000 $500

58 Preview Tell me about something you used to really like that you do not really care about anymore.

59 Changes in Market Equilibrium
How do shifts in supply affect market equilibrium? How do shifts in demand affect market equilibrium? How can we use supply and demand curves to analyze changes in market equilibrium?

60 Shifts in Supply Understanding a Shift
Since markets tend toward equilibrium, a change in supply will set market forces in motion that lead the market to a new equilibrium price and quantity sold. Excess Supply A surplus is a situation in which quantity supplied is greater than quantity demanded. If a surplus occurs, producers reduce prices to sell their products. This creates a new market equilibrium. A Fall in Supply The exact opposite will occur when supply is decreased. As supply decreases, producers will raise prices and demand will decrease.

61 Shifts in Demand Excess Demand
A shortage is a situation in which quantity demanded is greater than quantity supplied. Search Costs Search costs are the financial and opportunity costs consumers pay when searching for a good or service. A Fall in Demand When demand falls, suppliers respond by cutting prices, and a new market equilibrium is found.

62 Analyzing Shifts in Supply and Demand
$800 $600 $400 $200 Price Output (in millions) Graph A: A Change in Supply 1 2 3 4 5 Graph B: A Change in Demand Output (in thousands) $60 $50 $40 $30 $20 $10 900 800 700 600 500 400 300 200 100 Price Original supply Demand a New demand c b New supply b c Supply Original demand a Graph A shows how the market finds a new equilibrium when there is an increase in supply. Graph B shows how the market finds a new equilibrium when there is an increase in demand.

63 Section 2 Assessment 1. When a new equilibrium is reached after a fall in demand, the new equilibrium has a (a) lower market price and a higher quantity sold. (b) higher market price and a higher quantity sold. (c) lower market price and a lower quantity sold. (d) higher market price and a lower quantity sold. 2. What happens when any market is in disequilibrium and prices are flexible? (a) market forces push toward equilibrium (b) sellers waste their resources (c) excess demand is created (d) unsold perishable goods are thrown out Want to connect to the PHSchool.com link for this section? Click Here!

64 Section 2 Assessment 1. When a new equilibrium is reached after a fall in demand, the new equilibrium has a (a) lower market price and a higher quantity sold. (b) higher market price and a higher quantity sold. (c) lower market price and a lower quantity sold. (d) higher market price and a lower quantity sold. 2. What happens when any market is in disequilibrium and prices are flexible? (a) market forces push toward equilibrium (b) sellers waste their resources (c) excess demand is created (d) unsold perishable goods are thrown out Want to connect to the PHSchool.com link for this section? Click Here!


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