Lecture 02 Demand, Supply and Market Equilibrium
The Basic Decision-Making Units in the Economy: Firms and Households
Firms and Households A firm is an organization that transforms resources into products Firms are the primary producing units in a market economy. Households are the consuming units in an economy.
The Entrepreneur The entrepreneur is the person who organizes, manages, and assumes the risks of a firm, taking a new idea or a new product and turning it into a successful business.
Markets Product Factor Product or output markets are the markets in which goods and services are exchanged. Input or Factor markets are the markets in which resources used to produce products are exchanged.
Labor Markets Labor markets are the input markets in which households supply work for wages to firms that demand labor.
Capital Markets Capital markets are the input markets in which households supply their savings, for interest or for claims to future profits, to firms that demand funds in order to buy capital goods.
Land Markets Land markets are the input markets in which households supply land or other real property in exchange for rent.
The Circular Flow A circular flow diagram describes the interaction of firms and households in markets for outputs and inputs.
The Circular Flow Output Markets (Goods & Services) Supply Demand House holds Firms Input Markets: Labor (wages) Capital (interest) Land (rent) Supply Demand
The quantity demanded represents the amount of a product that a household buy in a given time period at the current market price. Demand in the Product Markets A household’s decision about what quantity of a product to demand depends on a number of factors...
Determinants of Household Demand: • PRICE of the product • INCOME available • Amount of accumulated WEALTH • PRICES OF RELATED PRODUCTS • TASTESandPREFERENCES • EXPECTATIONS with respect to future income, wealth, and prices
The Demand Schedule A demand schedule is a table or chart showing how much of a given product a household would be willing to buy at different prices.
The Demand Curve The demand curve is a graph illustrating how much of a given product a household would be willing to buy at different prices. Demand curves are usually derived from demand schedules.
The Demand Curve P D Q 0
Anna’s Demand Schedule for Telephone Calls - (Table 4.1) Price (per call) $ 0 .50 3.50 7.00 10.00 15.00 Quantity Demanded (calls per month) 30 25 7 3 1 0
Price $15.00 $10.00 $7.50 $3.50 $ .50 0 1 3 7 25 30 Quantity demanded Anna’s Demand Curve -(Figure 4.2)
The Law of Demand There is a negative, or inverse, relationship between the quantity of a good demanded and its price. This means that demand curves typically have a negative slope.
Other Determinants of Household Demand: 1) Income and Wealth Income: The total of all earnings received by a household in a given period of time Wealth: The total value of what a household owns less what it owes
Income as a Determinant of Demand Normal Goods:Goods for which demand goes up when income is higher and for which demand goes down when income is lower Inferior Goods:Goodsfor which demand falls when income rises.
Prices of Other Goods and Services as Determinants of Demand Substitutes:Goods that can serve as replacements for one another; when the price of one increases, demand for the other goes up - Perfect substitutes are identical products. Complements: Goods that ‘go together’; when the price of one increases, demand for the other goes down.
Other Determinants of Household Demand: Tastes and Preferences - These are quite subjective and tend to change over time. Expectations - With respect to future income, wealth, prices, and availability.
Changes in Quantity Demanded vs. Changes in Demand: Important Distinction!! Changes in quantity demandedimply movement along a demand curve. Changes in demand imply a shift in the entire demand curve.
Price $15.00 $10.00 $7.50 $3.50 D $ .50 0 1 3 7 25 30 Quantity demanded Anna’s Demand for Telephone Calls - A Change in Quantity Demanded Change in quantity demanded from 3 to 7 caused by a change in price from $7.50 to $3.50
Anna’s Demand for Telephone Calls - A Change in Demand Change in demand caused by a change in a demand factor other than price $15.00 $10.00 $7.50 D2 $3.50 D1 $ .50 0 1 3 7 25 30 Quantity demanded
Changes in Demand- Income Changes - Income Rises P P D2 D1 D2 D1 Q Q Demand for inferior good shifts left Demand for normal good shifts right
Changes in Demand- Prices of Related Goods - P Price of hamburger rises P P Q Quantity of hamburger demanded falls D2 D1 D1 D2 Q Q Demand for substitute good (chicken) shifts right Demand for complement good (catsup) shifts left
From Household to Market Demand Demand for a good or service can be defined for an individual household, or for a group of households that make up a market.
Market Demand- Defined - Market demand may be defined as the sum of all the quantities of a good or service demanded per period by all the households buying in the market for that good or service.
P DC DB $3.50 $3.50 $1.50 $1.50 0 0 0 3 Qd 4 9 Qd 4 8 Qd Market Demand Price $3.50 $1.50 0 8 20 Qd Deriving market demand from the individual demand curves: P DA
Supply in Output Markets A firm’s decision about what quantity of a product to supply depends on a number of factors...
Quantity Supplied The quantity supplied represents the number of units of a product that a firm would be willing and able to offer for sale at a particular price during a given time period
Factors Determining Firm Supply: PRICE of the product COST of producing the product - Prices of required inputs - Technologies used to produce the product PRICES of RELATED products
The Law of Supply There is a positive, or direct, relationship between the quantity of a good supplied and its price. This means that supply curves typically have a positive slope.
The Supply Schedule and Supply Curve A supply schedule is a table, or chart, showing how much of a product firms will supply at different prices. A supply curve is the graphical representation of a supply schedule.
Clarence Brown’s Soybean Supply Schedule Price per bushel $ 1.50 1.75 2.25 3.00 4.00 Bushels per year 0 10,000 20,000 30,000 45,000
Price $4.00 S $3.00 $2.25 $1.75 $1.50 0 10 20 30 40 50 Quantity demanded (1,000s) Clarence Brown’s Soybean Supply Curve
Changes in Quantity Supplied vs. Changes in Supply: IMPORTANT DISTINCTION ! Changes in quantity suppliedimply movement along a supply curve. Changes in supplyimply a shift in the entire supply curve.
$4.00 $3.00 $2.25 $1.75 $1.50 0 10 20 30 40 50 Quantity demanded (1,000s) A Change in the Quantity Supplied of Clarence Brown’s Soybeans P S Change in quantity supplied from 10 to 20 caused by a change in price from $1.75 to $2.25
A Shift in Clarence Brown’s Soybean Supply S1 Price $4.00 S2 $3.00 Change in supply caused by a change in a supply factor other than price $2.25 $1.75 $1.50 0 10 20 30 40 50 Quantity demanded (1,000s)
Changes in Quantity Supplied vs. Changes in Supply: P P S1 S S2 Q Q An increase in supply An increase in the quantity supplied
From Individual Firm to Market Supply The supply of a good or service can be defined for an individual firm, or for a group of firms that make up a market or an industry.
Market Supply The sum of all the quantities of a good or service supplied per period by all the firms selling in the market for that good or service. As with market demand, market supply is the horizontal summation of the individual firms’ supply curves.
From Individual Firm to Market Supply Firm A’s supply Firm B’s supply P P SB SA 3.00 3.00 1.75 1.75 Q Q 10,000 30,000 5,000 10,000 P SA+B 3.00 1.75 Market Supply Curve Q 25,000 65,000
Market Equilibrium The operation of the market depends on the interaction between suppliers and demanders.
Market Equilibrium An equilibrium is the condition that exists when quantity supplied is equal to quantity demanded. At equilibrium, there is no tendency for the market price to change.
Market Equilibrium P S E PE D Q QE
S $2.50 D 0 35 Bushels of soybeans (1,000s) The market for soybeans in equilibrium: P
Excess Demand Excess Demand is the condition that exists when quantity demanded exceeds quantity supplied at the current price.
At a price of $1.75 there is Excess Demand in the Soybean Market: P S $2.50 $1.75 D Q 0 25 35 50