曼昆微观经济学.pptx

会计学1曼昆微观经济学曼昆微观经济学Learning Objectivesn nExamine what items are included in a firms costs of productionn nAnalyze the link between a firms production process and its total costsn nLearn the meaning of average total cost and marginal cost and how they are relatedn nConsider the shape of a typical firms cost curvesn nExamine the relationship between short-run and long-run costs第1页/共52页The Market Forces of Supply and Demandn nSupply and demand are the two words that economists use most often.n nSupply and demand are the forces that make market economies work.n nModern microeconomics is about supply,demand,and market equilibrium.第2页/共52页WHAT ARE COSTS?n nAccording to the Law of Supply:n nFirms are willing to produce and sell a greater Firms are willing to produce and sell a greater quantity of a good when the price of the good is quantity of a good when the price of the good is high.high.n nThis results in a supply curve that slopes upward.This results in a supply curve that slopes upward.第3页/共52页WHAT ARE COSTS?n nThe Firms Objectiven nThe economic goal of the firm is to maximize The economic goal of the firm is to maximize profits.profits.第4页/共52页Total Revenue,Total Cost,and ProfitTotal Revenue,Total Cost,and Profitn nTotal Revenuen nThe amount a firm receives for the sale of its output.The amount a firm receives for the sale of its output.n nTotal Costn nThe market value of the inputs a firm uses in The market value of the inputs a firm uses in production.production.第5页/共52页Total Revenue,Total Cost,and ProfitTotal Revenue,Total Cost,and Profitn nProfit is the firms total revenue minus its total cost.Profit=Total revenue Total costProfit=Total revenue Total cost第6页/共52页Costs as Opportunity CostsCosts as Opportunity Costsn nA firms cost of production includes all the opportunity costs of making its output of goods and services.n nExplicit and Implicit Costsn nA firms cost of production include explicit costs and A firms cost of production include explicit costs and implicit costs.implicit costs.n nExplicitExplicit costs are input costs that require a direct outlay of costs are input costs that require a direct outlay of money by the firm.money by the firm.n nImplicitImplicit costs are input costs that do not require an outlay costs are input costs that do not require an outlay of money by the firm.of money by the firm.第7页/共52页Economic Profit versus Accounting ProfitEconomic Profit versus Accounting Profitn nEconomists measure a firms economic profit as total revenue minus total cost,including both explicit and implicit costs.n nAccountants measure the accounting profit as the firms total revenue minus only the firms explicit costs.第8页/共52页Economic Profit versus Accounting ProfitEconomic Profit versus Accounting Profitn nWhen total revenue exceeds both explicit and implicit costs,the firm earns economic profit.n nEconomic profit is smaller than accounting profit.Economic profit is smaller than accounting profit.第9页/共52页Figure 1 Economic versus AccountantsFigure 1 Economic versus AccountantsCopyright 2004 South-WesternRevenueTotalopportunitycostsHow an EconomistViews a FirmHow an AccountantViews a FirmRevenueEconomicprofitImplicitcostsExplicitcostsExplicitcostsAccountingprofit第10页/共52页PRODUCTION AND COSTSn nThe Production Functionn nThe The production functionproduction function shows the relationship between shows the relationship between quantity of inputs used to make a good and the quantity of inputs used to make a good and the quantity of output of that good.quantity of output of that good.第11页/共52页The Production Function The Production Function n nMarginal Productn nThe The marginal productmarginal product of any input in the production of any input in the production process is the increase in output that arises from an process is the increase in output that arises from an additional unit of that input.additional unit of that input.第12页/共52页The Production Function n nDiminishing Marginal Productn nDiminishing marginal productDiminishing marginal product is the property whereby is the property whereby the marginal product of an input declines as the the marginal product of an input declines as the quantity of the input increases.quantity of the input increases.n nExample:As more and more workers are hired at a firm,Example:As more and more workers are hired at a firm,each additional worker contributes less and less to each additional worker contributes less and less to production because the firm has a limited amount of production because the firm has a limited amount of equipment.equipment.第13页/共52页Figure 2 Hungry Helens Production FunctionFigure 2 Hungry Helens Production FunctionCopyright 2004 South-WesternQuantity ofOutput(cookiesper hour)150140130120110100908070605040302010Number of Workers Hired012345Production function第14页/共52页The Production Function The Production Function n nDiminishing Marginal Product n nThe slope of the production function measures the The slope of the production function measures the marginal product of an input,such as a worker.marginal product of an input,such as a worker.n nWhen the marginal product declines,the production When the marginal product declines,the production function becomes flatter.function becomes flatter.第15页/共52页From the Production Function to the Total-Cost CurveFrom the Production Function to the Total-Cost Curven nThe relationship between the quantity a firm can produce and its costs determines pricing decisions.n nThe total-cost curve shows this relationship graphically.第16页/共52页Table 3 A Production Function and Total Cost:Hungry Table 3 A Production Function and Total Cost:Hungry Helens Cookie FactoryHelens Cookie FactoryCopyright2004 South-Western第17页/共52页Figure 3 Hungry Helens Total-Cost CurveFigure 3 Hungry Helens Total-Cost CurveCopyright 2004 South-WesternTotalCost$8070605040302010Quantityof Output(cookies per hour)01020 30150130110907050401401201008060Total-costcurve第18页/共52页THE VARIOUS MEASURES OF COSTn nCosts of production may be divided into fixed costs and variable costs.第19页/共52页Fixed and Variable CostsFixed and Variable Costsn nFixed costs are those costs that do not vary with the quantity of output produced.n nVariable costs are those costs that do vary with the quantity of output produced.第20页/共52页Fixed and Variable CostsFixed and Variable Costsn nTotal Costsn nTotal Fixed Costs(Total Fixed Costs(TFCTFC)n nTotal Variable Costs(Total Variable Costs(TVCTVC)n nTotal Costs(Total Costs(TCTC)n nTCTC=TFCTFC+TVCTVC第21页/共52页Table 4 The Various Measures of Cost:Thirsty Thelmas Table 4 The Various Measures of Cost:Thirsty Thelmas Lemonade StandLemonade StandCopyright2004 South-Western第22页/共52页Fixed and Variable CostsFixed and Variable Costsn nAverage Costsn nAverage costs can be determined by dividing the Average costs can be determined by dividing the firms costs by the quantity of output it produces.firms costs by the quantity of output it produces.n nThe average cost is the cost of each typical unit of The average cost is the cost of each typical unit of product.product.第23页/共52页Fixed and Variable CostsFixed and Variable Costsn nAverage Costsn nAverage Fixed Costs(Average Fixed Costs(AFCAFC)n nAverage Variable Costs(Average Variable Costs(AVCAVC)n nAverage Total Costs(Average Total Costs(ATCATC)n nATCATC=AFCAFC+AVCAVC第24页/共52页Average CostsAverage Costs第25页/共52页Table 2 The Various Measures of Cost:Thirsty Table 2 The Various Measures of Cost:Thirsty Thelmas Lemonade StandThelmas Lemonade StandCopyright2004 South-Western第26页/共52页Fixed and Variable CostsFixed and Variable Costsn nMarginal Costn nMarginal costMarginal cost (MCMC)measures the increase in total cost)measures the increase in total cost that arises from an extra unit of production.that arises from an extra unit of production.n nMarginal cost helps answer the following question:Marginal cost helps answer the following question:n nHow much does it cost to produce an additional unit of How much does it cost to produce an additional unit of output?output?第27页/共52页Marginal CostMarginal Cost第28页/共52页Marginal Cost Thirsty Thelmas Lemonade Stand第29页/共52页Figure 4 Thirsty Thelmas Total-Cost CurvesFigure 4 Thirsty Thelmas Total-Cost CurvesCopyright 2004 South-WesternTotal Cost$15.0014.0013.0012.0011.0010.009.008.007.006.005.004.003.002.001.00Quantityof Output(glasses of lemonade per hour)014327659810Total-cost curve第30页/共52页Figure 5 Thirsty Thelmas Average-Cost and Marginal-Cost Figure 5 Thirsty Thelmas Average-Cost and Marginal-Cost CurvesCurvesCopyright 2004 South-WesternCosts$3.503.253.002.752.502.252.001.751.501.251.000.750.500.25Quantityof Output(glasses of lemonade per hour)014327659810MCATCAVCAFC第31页/共52页Cost Curves and Their ShapesCost Curves and Their Shapesn nMarginal cost rises with the amount of output produced.n nThis reflects the property of This reflects the property of diminishing marginal diminishing marginal productproduct.第32页/共52页Cost Curves and Their ShapesCost Curves and Their Shapesn nThe average total-cost curve is U-shaped.n nAt very low levels of output average total cost is high because fixed cost is spread over only a few units.n nAverage total cost declines as output increases.n nAverage total cost starts rising because average variable cost rises substantially.第33页/共52页Cost Curves and Their ShapesCost Curves and Their Shapesn nThe bottom of the U-shaped ATC curve occurs at the quantity that minimizes average total cost.This quantity is sometimes called the efficient scale of the firm.第34页/共52页Figure 5 Thirsty Thelmas Average-Cost and Marginal-Cost Figure 5 Thirsty Thelmas Average-Cost and Marginal-Cost CurvesCurvesCopyright 2004 South-WesternCosts$3.503.253.002.752.502.252.001.751.501.251.000.750.500.25Quantityof Output(glasses of lemonade per hour)014327659810ATC第35页/共52页Cost Curves and Their Shapes Cost Curves and Their Shapes n nRelationship between Marginal Cost and Average Total Costn nWhenever marginal cost is less than average total Whenever marginal cost is less than average total cost,average total cost is falling.cost,average total cost is falling.n nWhenever marginal cost is greater than average total Whenever marginal cost is greater than average total cost,average total cost is rising.cost,average total cost is rising.n nThe marginal-cost curve crosses the average-total-The marginal-cost curve crosses the average-total-cost curve at the cost curve at the efficient scaleefficient scale.n nEfficient scale is the quantity that minimizes average total Efficient scale is the quantity that minimizes average total cost.cost.第36页/共52页Figure 5 Thirsty Thelmas Average-Cost and Marginal-Cost Figure 5 Thirsty Thelmas Average-Cost and Marginal-Cost CurvesCurvesCopyright 2004 South-WesternCosts$3.503.253.002.752.502.252.001.751.501.251.000.750.500.25Quantityof Output(glasses of lemonade per hour)014327659810ATCMC第37页/共52页Typical Cost CurvesTypical Cost CurvesIt is now time to examine the relationships that exist between the It is now time to examine the relationships that exist between the different measures of cost.different measures of cost.第38页/共52页Big Bobs Cost Curves第39页/共52页Figure 6 Big Bobs Cost CurvesFigure 6 Big Bobs Cost CurvesCopyright 2004 South-Western(a)Total-Cost Curve$18.0016.0014.0012.0010.008.006.004.00Quantity of Output(bagels per hour)TC42681412102.00TotalCost0第40页/共52页Figure 6 Big Bobs Cost CurvesFigure 6 Big Bobs Cost CurvesCopyright 2004 South-Western(b)Marginal-and Average-Cost CurvesQuantity of Output(bagels per hour)Costs$3.002.502.001.501.000.5004268141210MCATCAVCAFC第41页/共52页Typical Cost Curves Typical Cost Curves n nThree Important Properties of Cost Curvesn nMarginal cost eventually rises with the quantity of Marginal cost eventually rises with the quantity of output.output.n nThe average-total-cost curve is U-shaped.The average-total-cost curve is U-shaped.n nThe marginal-cost curve crosses the average-total-The marginal-cost curve crosses the average-total-cost curve at the minimum of average total cost.cost curve at the minimum of average total cost.第42页/共52页COSTS IN THE SHORT RUN AND IN THE LONG RUNCOSTS IN THE SHORT RUN AND IN THE LONG RUNn nFor many firms,the division of total costs between fixed and variable costs depends on the time horizon being considered.n nIn the short run,some costs are fixed.In the short run,some costs are fixed.n nIn the long run,fixed costs become variable costs.In the long run,fixed costs become variable costs.第43页/共52页COSTS IN THE SHORT RUN AND IN THE LONG RUNCOSTS IN THE SHORT RUN AND IN THE LONG RUNn nBecause many costs are fixed in the short run but variable in the long run,a firms long-run cost curves differ from its short-run cost curves.第44页/共52页Figure 7 Average Total Cost in the Short and Long RunFigure 7 Average Total Cost in the Short and Long RunCopyright 2004 South-WesternQuantity ofCars per Day0AverageTotalCost1,200$12,000ATC in shortrun withsmall factoryATC in shortrun withmedium factoryATC in shortrun withlarge factoryATC in long run第45页/共52页Economies and Diseconomies of ScaleEconomies and Diseconomies of Scalen nEconomies of scale refer to the property whereby long-run average total cost falls as the quantity of output increases.n nDiseconomies of scale refer to the property whereby long-run average total cost rises as the quantity of output increases.n nConstant returns to scale refers to the property whereby long-run average total cost stays the same as the quantity of output increases第46页/共52页Figure 7 Average Total Cost in the Short and Long RunFigure 7 Average Total Cost in the Short and Long RunCopyright 2004 South-WesternQuantity ofCars per Day0AverageTotalCost1,200$12,0001,00010,000EconomiesofscaleATC in shortrun withsmall factoryATC in shortrun withmedium factoryATC in shortrun withlarge factoryATC in long runDiseconomiesofscaleConstantreturns toscale第47页/共52页Summaryn nThe goal of firms is to maximize profit,which equals total revenue minus total cost.n nWhen analyzing a firms behavior,it is important to include all the opportunity costs of production.n nSome opportunity costs are explicit while other opportunity costs are implicit.第48页/共52页Summaryn nA firms costs reflect its production process.n nA typical firms production function gets flatter as the quantity of input increases,displaying the property of diminishing marginal product.n nA firms total costs are divided between fixed and variable costs.Fixed costs do not change when the firm alters the quantity of output produced;variable costs do change as the firm alters quantity of output produced.第49页/共52页Summaryn nAverage total cost is total cost divided by the quantity of output.n nMarginal cost is the amount by which total cost would rise if output were increased by one unit.n nThe marginal cost always rises with the quantity of output.n nAverage cost first falls as output increases and then rises.第50页/共52页Summaryn nThe average-total-cost curve is U-shaped.n nThe marginal-cost curve always crosses the average-total-cost curve at the m