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Unit 2. Chapters 3, 18, and 19. 3. Demand, Supply, and Market Equilibrium. Chapter Objectives. Demand Defined and What Affects It Supply Defined and What Affects It How Supply & Demand Together Determine Market Equilibrium
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Unit 2 Chapters 3, 18, and 19
3 Demand, Supply, and Market Equilibrium
Chapter Objectives • Demand Defined and What Affects It • Supply Defined and What Affects It • How Supply & Demand Together Determine Market Equilibrium • How Changes in Supply and Demand Affect Equilibrium Prices and Quantities • Government-Set Prices and their Implications for Surpluses & Shortages
3.1 3.2 3.3 3.4 Demand • Demand Defined • Demand Schedule • Law of Demand • Diminishing Marginal Utility • Income Effect • Substitution Effect • Demand Curve • Market Demand
4.1: What is demand? • Demand – the desire to have a good or service and the ability to pay for it. • The 2 factors of desire and ability are both necessary • Ex. I have the desire to go on a European vacation, but I can not afford it. Therefore, I do not possess demand for it.
Demand Defined • Expressed on a schedule or curve that shows the various amounts of a product that consumers are willing and able to purchase at each of a series of possible prices during a specified period of time • Show quantities of a product that will be purchased at various psb prices, other things equal
Demand Schedule • Table showing how much of a product an individual is willing & able to buy @ each price in the market. • Market demand schedule – table showing how much all consumers are willing to buy @ each price • See p.45 Figure 3.1
Law of Demand • Inverse relationship between price and quantity demanded • States that when price increases, quantity demanded decreases • When P. dec., QD. inc. • Ppl buy less at higher prices, more at lower prices
Explanations of the Law of Demand • Why the inverse relationship b/w P and QD? • 1. Common sense—think about it! • 2. Diminishing marginal utility – marginal benefit from using each additional unit of a product during a given period will decline. • Ex. You get more satisfaction from the first glass of lemonade than the second, third, fourth…and are therefore not willing to pay as much for each additional unit
Explanations of the Law of Demand • 3. Income and substitution effects • income effect – change in the amount that consumers will buy b/c the purchasing power of their income changes, although income itself doesn’t change. • Ex. You go to the store to buy ground beef, it is on sale, you feel wealthier and buy more.
Explanations of the Law of Demand • 2. substitution effect – change in the amount that people will buy b.c they substitute goods instead. • Ex. You go to the store to buy ground beef but you see ground turkey is on sale for ½ the price so you buy that instead.
Demand Curve • Graph showing how much of a product an individual will buy @ each price • Graphic representation of demand schedule and law of demand • Slopes downward from left to right • Market demand curve – graph showing data from market demand schedule • Price on Y-axis, Quantity on X-axis • See p.45 Figure 3.1
6 5 4 3 2 1 0 Price (per bushel) 10 20 30 40 50 60 70 80 Quantity Demanded (bushels per week) Individual Demand P Individual Demand P Qd $5 4 3 2 1 10 20 35 55 80 D Q
Change in Quantity Demanded • -change in the amt. of a product consumers will buy b/c of a change in price • Shown by a movement along the demand curve
Individual Demand Determinants of Demand • Tastes • Number of Buyers • Income • Normal Goods • Inferior Goods • Price of Related Goods • Substitute Good • Complementary Good • Unrelated Goods • Consumer Expectations
Change in Demand • Something prompts consumers to buy different amounts @ every price • Represented by shifts of the demand curve • Inc. in demand – curve shifts right • Dec. in demand – curve shifts left • Influenced by 6factors
Factor 1: Income • If consumer income inc., demand inc. • If income dec., demand dec. Ex. a factory closes, ppl lose jobs, income falls and demand dec.
2 types of goods: • Normal goods – goods for which demand inc. as income inc. • Ex. most goods such as TVs, steaks, IPODS, etc… • Inferior goods - goods for which demand dec. as income inc. • Ex. Generics, Ramen noodles, etc…
Factor 2: Market Size • # of consumers, population changes, seasonal tourist trends • If market size inc., demand inc.
Factor 3: Consumer tastes • Advertising, trends, styles, popularity, celebrity endorsements • If consumer tastes inc., demand inc.
Factor 4: Consumer Expectations • Refers to expectations of future prices • If consumers expect a future price inc., current demand inc.
Factor 5: Substitute Goods • g/s that can be used in place of each other • Ex. Coke and Pepsi, wireless phones and traditional phones • If demand for substitute inc., demand for original item dec.
Factor 6: Complements • Goods used together so a rise in the demand for one inc. as the demand for another inc. • Ex. digital cameras and photo printers, cars and gas
Individual Demand Demand Can Increase or Decrease P 6 5 4 3 2 1 0 Individual Demand Increase in Demand P Qd $5 4 3 2 1 10 20 35 55 80 Price (per bushel) D2 D1 Decrease in Demand D3 Q 2 4 6 8 10 12 14 16 18 Quantity Demanded (bushels per week)
Individual Demand Demand Can Increase or Decrease An Increase in Demand Means a Movement of the Line P 6 5 4 3 2 1 0 Individual Demand A Movement Between Any Two Points on a Demand Curve is Called a Change in Quantity Demanded P Qd $5 4 3 2 1 10 20 35 55 80 Price (per bushel) D2 D1 Decrease in Demand D3 Q 2 4 6 8 10 12 14 16 18 Quantity Demanded (bushels per week)
Supply • Supply Defined • Supply Schedule • Law of Supply • Revenue Implications • Marginal Cost • Supply Curve • Market Supply
5.1: What is supply? • Willingness and ability of producers to offer a g/s for sale • Expressed as a schedule or curve showing the various amounts of a product that producers are willing and able to sell at each of a series of psb prices during a specified period • Producer = anyone who is willing to provide a g/s • Ex. worker, company, farmers, etc… • Profit motivates producers to inc. supply
Law of Supply • Direct (positive) relationship between P and QSS • When P. inc., QS inc. • When P. dec., QS dec.
Supply Schedule • Table showing how much of a g/s an individual producer is willing and able to sell @ each P. • Market supply schedule – lists how much of a g/s all producers will sell @ each P. • See p.51 Figure 3.4
Supply Curve • Supply schedule data in graphic form • Shows law of supply in graph form • Slopes upward from left to right • Market supply curve – market supply schedule in graph form • See p.102 Figure 3.4
Individual Supply P 6 5 4 3 2 1 0 Individual Supply S1 P Qs $5 4 3 2 1 60 50 35 20 5 Price (per bushel) Q 10 20 30 40 50 60 70 Quantity Supplied (bushels per week)
5.3: What Factors Affect Supply? • Changes in quantity supplied – inc. or dec. in the amount of a g/s that producers are willing to sell b/c of a change in P. • -shown by movement to different points along the S. curve
Changes in Supply • Occur when a change in the marketplace causes producers to sell different amounts @ every price. • Inc. in S, curve shifts right • Dec. in S, curve shifts left • 6 Factors influence supply
Individual Supply Determinants of Supply • Resource Prices • Technology • Taxes and Subsidies • Prices of Other Goods • Producer Expectations • Number of Sellers
Factor 1: Input Costs • Price of resources used to make products • Ex. Cost of nuts used to make candy bars • Input costs inc., Supply dec.
Labor Productivity • Amt of a g/s a person can produce in a given time • Ex. More skilled & educated workers, labor strike • Inc. productivity, Supply inc.
Factor 2: Government Action • Excise tax – taxes production/sale of certain goods • Tax inc., Supply dec. • Subsidy – gov. payment for part of production cost • Subsidy inc., supply inc. • Regulation – rules/laws controlling business beh. (Ex. Pollution, worker safety) • New regulation, Supply dec.
Factor 3: Technology • Applying science & innovation to production • Ex. Robots on assembly line, computers, etc… • Inc. in technology, Supply inc.
Factor 4: Prices of Other Goods • Substitution in production that may occur when higher prices of other goods a seller produces entice the producer to switch production to those other goods in order to increase profits. • See example on page 52.
Factor 5: Producer Expectations • If producers expect a future P. inc, they will withhold current supply.
Factor 6: # of Producers • More producers of a product, Supply inc. • Ex. Fast food restaurants, auto manufacturers
Individual Supply Supply Can Increase or Decrease P 6 5 4 3 2 1 0 S3 Individual Supply S1 S2 P Qs $5 4 3 2 1 60 50 35 20 5 Price (per bushel) Q 2 4 6 8 10 12 14 Quantity Supplied (bushels per week)
Individual Supply Supply Can Increase or Decrease A Movement Between Any Two Points on a Supply Curve is Called a Change in Quantity Supplied P 6 5 4 3 2 1 0 S3 Individual Supply S1 S2 P Qs $5 4 3 2 1 60 50 35 20 5 Price (per bushel) An Increase in Supply Means a Movement of the Line Q 2 4 6 8 10 12 14 Quantity Supplied (bushels per week)
3.1 Market Equilibrium • Equilibrium Price • Equilibrium Quantity • Surplus • Shortage • Rationing Function of Prices
6.1: Seeking Equilibrium: Demand and Supply • Market equilibrium – situation in which the quantity demanded for a service is equal to the quantity supplied • Two curves intersect at point of market equilibrium. • Equilibrium price(market-clearing price) – price at which QS = QD; equilibrium quantity can also be determined
Reaching the Equilibrium Price • Trial and error may be necessary for the market to arrive at equilibrium. • Market may have a surplus: QS>QD • Market may have a shortage: QD>QS
Surpluses and Shortages • Surpluses happen when prices are too high relative to demand (excess supply) • With surplus, prices tend to fall; producers cut back production • Shortages happen when prices are too low relative to demand (excess demand) • With shortage, prices rise; producers increase quantity supplied
Market Equilibrium 200 Buyers & 200 Sellers Market Demand 200 Buyers Market Supply 200 Sellers 6 5 4 3 2 1 0 6,000 Bushel Surplus S P Qd P Qs $5 4 3 2 1 2,000 4,000 7,000 11,000 16,000 $5 4 3 2 1 12,000 10,000 7,000 4,000 1,000 $4 Price Floor Price (per bushel) 3 $2 Price Ceiling 7,000 Bushel Shortage D 7 2 4 6 8 10 12 14 16 18 Bushels of Corn (thousands per week)
Rationing Function of Prices • Ability of the forces of S and D to establish a P at which selling and buying decisions are consistent • At equilibrium, there is no shortage and no surplus
Efficient Allocation • Competitive market also allocate societies’ • resources efficiently • Results in productive efficiency – production of any particular good in the least costly way • Also results in allocative efficiency – the particular mix of G&S most highly valued by society, assuming minimum-cost production. • Demand essentially reflects the MB of a good, while supply reflects MC of producing a good. At the intersection of the S and D curves, MB=MC, resulting in allocative efficiency!