微观经济学平狄克版第4章课件
立的。
Chapter 1
Slide 11
价格的变化与替代品和互补品
要分清商品是替代品或互补品，可以观察价格—消费曲线。 如果价格—消费曲线是向下倾斜的，那么，两种商品是替代品。 如果价格—消费曲线是向上倾斜的，那么，两种商品是互补品。 如果价格—消费曲线是水平的，那么，两种商品就是独立的。
D
TE
SE
U1
O
F2 F1
ES
IE
Chapter 1
食品 T
Slide 30
吉芬商品的收入效应替代效应及个人需求曲线
一个特例——吉芬商品 在理论上，收入效应可以大到使某种商品的需求曲线向上倾斜，这种商品称为吉 芬商品。
Chapter 1
Slide 31
[例4.2 汽油税的影响]
假设 需求的价格弹性 = -0.5 收入= 9,000美元 汽油价格 = 1美元
4
Chapter 1
12
20
食物数量
Slide 8
完全替代品的价格-消费曲线 Y
MRS<PX/PY A
红色为 IC曲线
MRS=PX/PY MRS>PX/PY
Chapter 1
B
X
Slide 9
互补品的价格-消费曲线 Y
U0
U1
A
E1 E0
B0
Min(aX,bY) aX bY
价格-消费曲线
X B1
原预算线
900 913.5 1200 D J
汽油消费量 B
Slide 33
4.3 市场需求
4.3.1从个人需求到市场需求 市场需求曲线
市场需求曲线描述了在商品的每一个价格水平下所对应的所有消费者的需求总量 。
Chapter 1
Slide 34
市场需求曲线的确定
价格 ($)
个人A (units)
食物 16
Slide 19
恩格尔曲线的形状：向后弯 收入 30
劣等商品的恩格尔 曲线向后弯曲。 20
10
劣等 正常
0
4
8
12
Chapter 1
食物 16
Slide 20
完全替代品的收入-消费曲线
Y 红色为 IC曲线
A
当无差异曲线的斜率大于预算 约束的斜率时，完全替代品的 收入-消费曲线与横轴重合； 若无差异曲线的斜率大于预算 约束的斜率，完全替代品的收 入-消费曲线与纵轴重合。
食物
Slide 4
价格-消费曲线 衣服
价格—消费曲线：将与食物的每一种 价格相对应的效用最大化的商品组合 点连结起来。
6
A
5
U1
B
4
价格—消费曲线 D
U3
U2
4
Chapter 1
12
20
食物
Slide 5
个人的食品需求曲线
食物的价格 E
$2.00
把不同的食物价格水平下，消费 者愿意购买的食物数量在P-Q坐 标上标出，得到个人需求曲线。
收入变化的对个人需求曲线的影响 食物的价格
在价格不变的情况下，收入 的提高会导致消费者的需求 曲线向右移动。
$1.00
E
G
H
Chapter 1
D3
D2 D1
4
10
16
食物数量
Slide 14
收入-消费曲线
收入—消费曲线描述了在每一个收入水平下，使消费者效用实现最大化的衣服与食物的 所有组合。
收入的增加使得预算线向右移动，沿着收入—消费曲线向上，消费量也增加了。 同时，随着收入的增加，需求曲线也向右移动。
$1.00 $.50
G 需求曲线 H
4
Chapter 1
12
20
食物数量
Slide 6
个人需求曲线
个人需求曲线：把单个消费者在各个价格水平下购买的商品数量联系起来得到。 个人需求曲线的两大特征:
1) 当我们沿着需求曲线向下移动时，我们所能获得效用水平不断增加。 2）当我们沿着需求曲线下移时，食物对衣服的MRS逐渐下降。当消费者购买更多食物的时
Chapter 1
Slide 10
替代品和互补品
1)
如果一种商品的价格上涨（下跌）导致另一种商品需求量的上升（下降），那么，这
两种商品就是替代品。例如，电影票与录像带。
2)
如果一种商品的价格上涨（下跌）导致另一种商品需求量的下降（上升），那么，这
两种商品就是互补品。例如，汽车与汽油。
3)
如果一种商品价格的变化对另一种商品的需求量没有影响，那么，这两种商品就是独
Chapter 1
Slide 32
[例4.2 汽油税的影响]
其他商品的支出 F A
征收汽油税又加上退还后的预算线
退税450美元，面临新的 预算线，消费者满足下降。
征收汽油税 后的预算线。 征收0.5汽油税后， 消费汽油900加仑。
Chapter 1
H
C
E
U2
U3 U1
最初，消费者在C点消费， 汽油1200，其他支出7800。
微观经济学平狄克版第4章课件
本章讨论的主题 个人需求 收入效应与替代效应 市场需求 消费者需求 连带外部效应 需求的经验估计
Chapter 1
Slide 2
4.1 个人需求（曲线）
个人需求：运用无差异曲线说明当食品的价格变化，单个消费者是如何做出消费选择 的。（推导出个人的食品需求曲线）
D
EF2 (从D点至B点)为新相对价格下，实际
收入提高，消费者增加对F的购买量(收入
B
效应)。
C2
替代效应
U2 U1
食物F
O
F1 总效应
E
S F2
T
收入效应
Chapter 1
Slide 27
正常品的替代效应、收入效应与个人需求曲线
替代效应：PF↓→消费者用便宜的F代替C→F的购买量↑ 收入效应：PF↓→消费者的实际收入↑→对正常品F的购买量↑ 因此， PF↓→F↑，正常商品的需求曲线向下倾斜。
候，食物的相对价值便下降了。
Chapter 1
Slide 7
个人需求曲线
食物价格
随着食物价格的下降，Pf/Pc 与MRS也同时下降。
E $2.00
$1.00 $.50
G 需求曲线 H
•E: Pf/Pc = 2/2 = 1 = MRS •G: Pf/Pc = 1/2 = .5 = MRS •H:Pf/Pc = .5/2 = .25 = MRS
Chapter 1
Slide 12
4.1.2 收入变化的影响 衣服
假设: Pf = $1， Pc = $2 I = $10, $20, $30
7 5 3
Chapter 1
收入—消费曲线
U2 B
D U3
在价格不变的条件下，收入 的提高会导致消费者改变其 市场篮子。
A
U1
4
10
16
食物
Slide 13
恩格尔曲线由收入消费曲线推导出来。 恩格尔曲线的形状：如果一种商品是正常商品，恩格尔曲线是向上倾斜的；如果一种
商品是劣等商品，恩格尔曲线就是向下倾斜的。
Chapter 1
Slide 18
恩格尔曲线的形状：向右上方倾斜 收入 30
20
正常商品的恩格尔 曲线向上倾斜。
10
0
4
8
12
Chapter 1
Chapter 1
B
X
Slide 21
互补品的收入-消费曲线
Min(aX,bY)
Y
aX bY
U0
U1
收入-消费曲线
A
E1
E0
ቤተ መጻሕፍቲ ባይዱ
X
B0
B1
Chapter 1
Slide 22
[例4.1 美国的消费支出]
支出项目
娱乐 自有住房 租用住房 保健护理 食物 衣服
收入组 (1993年美元)
10,000 以下
1,00019,000
Chapter 1
Slide 16
一种劣等商品 牛排 15
10
5 A 5
Chapter 1
收入—消费曲线
在A和B之间，牛排与汉堡包
C
都表现为一种正常商品。
U3 B
但是，在B和C之间，收入-消费 曲线向后弯曲，汉堡包就成了劣 等商品。
U2
U1
10
20
汉堡包 30
Slide 17
恩格尔曲线
恩格尔曲线（Engel curves）表示消费者的收入与某种商品的消费量之间的关系的曲 线。
需求有弹性：
P=80 ,Q=20 TR = 80*20 = 1600
价格下降到P=60 TR = 60*40 = 2400
TR提高(富有弹性的商品降价会增加消费 者的货币支出或生产者的销售收入)。
20 40 60
Chapter 1
Slide 26
正常商品的替代效应与收入效应 衣服C R
C1
A
食物价格下降，消费者的选择从A点移动到B点，消费量 增加了F1F2(总效应).
食品价格下降使两种商品相对价格变化，为 维持满足程度不变，消费者只需绿色线代表 的收入水平。F1E（从A点到D点）就是消费 者为维持U1不变，用便宜的F代替C而增加 的对F的购买量（替代效应）。
Chapter 1
Slide 15
正常商品和劣等商品
如果收入—消费曲线的斜率为正，意味着: 需求量随着收入的提高而增加。 商品需求的收入弹性为正值。 这种商品就是正常商品（normal good）。
如果收入—消费曲线的斜率为负，意味着: 需求量随着收入的提高而减少。 商品需求的收入弹性为负值。 这种商品就是劣等商品（ inferior good）。
平迪克中级微观经济学4
(平狄克，鲁宾费尔德，第四版)
LECTURE 4 生产者理论
1
一、生产
2
生产技术
结合投入品（生产要素）以获得一定产出。 投入品包括劳动、原材料、资本。 生产函数：
在既定技术条件下，每一特定组合的生产要素投入 的最高产出，显示在厂商有效运作中的技术可行性。
两要素生产函数：Q=F(K,L) 等产量线：图 PP4
1
1
2
3
4
5
14
Labor per month
完全可替代投入品的生产函数
等产量线上的所有点MRTS均相等； 给定产出量，任何投入品组合均可实现。
15
Isoquants When Inputs are Perfectly Substitutable
Capital per month
A
B
C Q1 Q2 Q3
18
规模报酬
衡量厂商规模和其产出之间的关系。 规模报酬递增：等产量线越来越密。 规模报酬恒定：等产量线分布均匀。 规模报酬递减：等产量线越来越稀。
19
Returns to Scale
Capital (machine hours)
Increasing Returns: The isoquants move closer together A
Output per Month 112 C 60 A 0 1 2 3 4 5 6 7 8 9 10
Labor per Month
D
Output per Month
30
E
B
20 10
0 1 2 3 4 5 6 7 8 9 10 per Month来自Labor边际回报递减法则
《微观经济学》平狄克教材
而获得两端收入的可能性小。
Chapter 5
Slide 19
不同概率分布的情形
概率
与工作2相比，工作1的收入 分布较离散，标准差也更大。
0.2
工作2
0.1
工作1
$1000
$1500
Chapter 5
$2000
收入
Slide 20
5.1 风险描述
决策（Decision making）
人们对待风险的态度会影响他们的决策。
Chapter 5
Slide 9
5.1 风险描述
假设Pr1，Pr2…… ，Pr n分别表示每一种可能性
结果的概率，而X1，X2……，X n分别代表每一 种可能性结果的值，那么，期望值的公式为：
E(X) Pr1X1 Pr2 X 2 ... Prn X n
Chapter 5
Slide 10
A
6
0
10
20
Chapter 5
30
收入
Slide 28
5.2 风险的偏好
风险爱好者
如果消费者在期望收入相同的确定性工作与 不确定性工作中选择了后者，那么，该消费 者就是风险爱好者（risk loving）。
例如：赌博、一些犯罪活动
Chapter 5
Slide 29
5.2 风险的偏好
风险爱好者
2 9,900 2 99.50
Slide 15
5.1 风险描述
计算方差
结果1 结果 2 方差 标准差
工作1 工作2
2,000 1,510
1,000 510
250,000 9,900
500.00 99.50
平狄克微观经济学(第八版)第四章
和B之间为正常商向后弯曲，它就
成了劣等品。
Copyright © 2013 Pearson Education, Inc. • Microeconomics • Pindyck/Rubinfeld, 8e.
8 of 50
恩格尔曲线
•恩格尔曲线将一种商品的
食物需求量的上升。
Copyright © 2013 Pearson Education, Inc. • Microeconomics • Pindyck/Rubinfeld, 8e.
17 of 50
收入和替代效应：劣等品
衣服 (单位/月）R
食物是劣等商品，因为价格变化
导致的收入效应是负值。不过，
A B
消费量与收入联系在一起。
•在(a)图中，食物是一种正 常商品，恩格尔曲线向上
倾斜。
•然而，在(b)图中，对于收 入在20美元以下的人来说，
汉堡包是一种正常商品；
而对于收入在20美元以上 的人来说，它则是一种劣
等品。
Copyright © 2013 Pearson Education, Inc. • Microeconomics • Pindyck/Rubinfeld, 8e.
个人需求和市场需求
• 个别需求 • 收入和替代效应 • 市场需求 • 消费者剩余 • 连带外部效应 • 需求的经验估计
Appendix: Demand Theory—A Mathematical Treatment
Prepared by: Fernando Quijano, Illustrator
Copyright © 2013 Pearson Education, Inc. • Microeconomics • Pindyck/Rubinfeld, 8e.
微观经济学第四章课件
三、厂商的目标
微观经济学中，假设厂商的
目标是追求利润最大化。 现实经济中，也有追求销售 收入或市场份额最大化的。 现代企业中，所有者与经营 者的分离，委托代理关系的 二、企业的本质： 存在，经营者可能会做出实 企业：在一定程度上是对市场 现自己利益最大化的决策， 的一种替代。 而这种决策可能是让企业偏 当交易成本高时，通过企业这 离利润最大化目标的。 一组织形式，使部分的市场交 易内部化，从而消除或降低部 本章仍以利润最大化为目标 来分析。 分市场交易所产生的高的交易 成本。
三、边际技术替代率（与效用论中的边际替代率比较）
1. 边际技术替代率的概念阐述 边际技术替代率（marginal rate of technical Substitution，MRTS）
是指在维持产量水平不变的条件下，增加一单位的某种生产要 素投入量所减少的另一种要素的投入的数量。
MRTS LK
（一）成本一定，产出量最大；
K
图示分析：
1. 成本一定，且各生产要素价 格一定，则等成本曲线固定。 2. 一定技术水平下，生产函数 已知，则可导出等产量线束。 3. 因此，满足“成本一定，产出 量最大”条件的必是等成本线与 等产量线的切点。 L
B
E
Q3
Q2
Q1 O A
经济角度分析：P143
可以证明，在均衡点，亦即生产 者实现产量最大化的要素组合， 必然会有：MPL/w= MPk/r
经济含义
七、扩展线
◆ 形成
当厂商投入的生产要素增加时，则用于购买生产要素的成本必 增加（故，等成本曲线发生变动）； 它的产出产量也必然增加（故，等产量曲线发生变动。）
所以，生产者均衡点也变动（即等产量曲线与等成本曲线的切 点）。
平狄克《微观经济学》(第7版)习题详解(第4章 个人需求和市场需求
平狄克《微观经济学》(第7版)习题详解(第4章个人需求和市场需求平狄克《微观经济学》(第7版)习题详解(第4章个人需求和市场需求borntowin经济学考研交流群<<平狄克《微观经济学》（第7版）第4章个人需求和市场需求课后复习题揭秘跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，例如您还须要更多考研资料，可选择经济学一对一在线咨询展开咨询。
1．说明下面各项中每一对之间的区别：（1）价格-消费曲线与需求曲线；（2）个人需求曲线与市场需求曲线；（3）恩格尔曲线与需求曲线；（4）收入效应与替代效应。
答：（1）价格-消费曲线与需求曲线的区别表现为：①价格-消费曲线就是所指在一种商品的价格水平和消费者收入水平维持不变时，另一种商品价格变动所对应的两种商品最佳出售女团点共同组成的轨迹。
市场需求曲线就是所指在维持总收入和其他条件维持不变的情况下，一种商品的价格变动所对应的消费数量变动的轨迹。
②从图像上看，价格-消费曲线的横轴和纵轴都是商品数量；而需求曲线的横轴是商品数量，纵轴是价格。
（2）个人市场需求曲线就是说明某一个消费者的消费市场需求数量与商品价格的函数关系的曲线；市场需求曲线就是说明整个消费群体的消费市场需求数量与商品价格的函数关系的曲线。
通过将个人市场需求曲线展开水平加总可以得出结论市场需求曲线。
两者的主要区别在于它们所表示的需求量的主体不同，个人需求曲线的主体是某一个消费者，市场需求曲线的主体是整个消费群体。
另外，两条曲线的需求价格弹性不同。
（3）市场需求曲线就是在维持总收入和其他条件维持不变的情况下，说明在各种可能将的价格下某一商品的市场需求数量的一条曲线。
平狄克 微观经济学 第七版 ppt课件
D
Q Q Q Q 1
3 e ppt课件
2
Q
46
发散型蛛网：需求弹性小于供给弹性
P
S
P3
P1 Pe P2
D
Q3Q1Qe Q2 Q4
Q
ppt课件
47
封闭型蛛网：需求弹性等于供给弹性
P
S
P1
Pe
Q1
Qe
Q2
ppt课件
D
Q
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第二章 消费者行为理论
任何经济体制实际上都是人的集合，因此， 经济学很自然地从个人行为开始进行分析：
4、需求的变动不存在时滞。
5、产品本身不易储存，应尽快出 售。
Q模td 型 f (Pt ) Qts (Pt1) Qtd Qts
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数学模型
Qdt Qst
Qdt Pt ( , 0) Qst Pt1( , 0)
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点弹性的公式与类型
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需求的价格弹性与销售收入
价格弹性大的物品，降价可以提高销售 收入；价格弹性小的物品，提价可以提 高销售收入。
马歇尔于1890年发表的 《经济学原理》，被看作是
与斯密《国富论》、李嘉图
《赋税原理》齐名的划时代
著作，成为当时最有影响的
完整版微观经济学(平狄克)图像.pptx
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• 收入变化
当收入—需求曲线的 斜率为负数时:
需求量随收入的 增加而减少。需求的 收入弹性为负值.
若价格相对比率保持不变
如果两种商品价格均上升， 但价格相对比率保持不变， 则预算线的斜率不变。但 预算线将与原来的预算线 平行并向内移动。
如果两种商品价格均下降， 但价格相对比率保持不变， 则预算线的斜率不变。但 预算线将与原来的预算线 平行并向外移 Solutions
K = C/r - (w/r)L
• 成本最小化的资本与劳动组合可写成：
– 在给定产出水平下，成本最小满足的条
件是：每1美元的投入增加到生产过程中
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去会有与之等值的产出增加。
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– 长期边际成本变化导致长期平均成本的变 化:
• 如果长期边际成本小于长期平均成本 （ LMC < LAC）, 长期平均成本（LAC） 将 下降；
Q = 8 - 2P
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线性需求曲线
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汽油的情况
耐用消费品如汽车
初级铜的情况
再生铜的情况
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短期弹性 和
长期弹性
价格控制的效应 价格
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如果被设定为不超过 Pmax, 产品供给下降到Q1， q需求数 量增加到Q2. 供给和需求之间
生产者均衡分析PPT课件
2.柯布—道格拉斯生产函数
Cobb-Dauglas生产函数是由数学家柯布和经济学 家道格拉斯于20世纪30年代初一起提出来的。起 函数的一般形式为：
Q=
ALK
其中，A、α和β为三个参数，0<α,β<1。
参数α和β的经济含义是：当α+β=1时，α和β分别 表示劳动和资本在生产过程中的相对重要性，α 为劳动所得在总产量中所占的份额，β为资本所得 在总产量中所占的份额。
能生产的最大产量，则生产函数可以写成： Q=f（X1，X2，…，Xn）
生产函数表示在一定时期内，在技术水平不变 的情况下，生产中所使用的各种生产要素的数 量与所生产的最大产量之间的关系。
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如果将各种投入的要素主要分为两种：劳动力 和资本，那么生产函数也可简化为如下形式：
Q=f（L，K） 其中，L表示劳动投入数量，K表示资本投入数 量。
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六、短期生产的三个阶段
第Ⅰ阶段：从O—L3阶段，由于不变要素资本的投 入量相对过多，生产者增加可变要素劳动的投入 量是有利的。电视机装配厂，制衣厂
第Ⅱ阶段：从L3—L4阶段，生产者进行短期生产的 决策区间。
第Ⅲ阶段：L4之后， 可变要素劳动的投入 量相对过多，生产者 减少可变要素劳动的 投入量是有利的。
QALK
如果 1 ，则Q(L,K)Q，则为规模报酬递增
如果 1 ，则Q(L,K)Q，则为规模报酬递减 如果 1 ，则Q(L,K)Q，则为规模报酬不变
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一般而言，在长期生产过程中，企业规模报酬 的变化呈现出如下规律：在一定规模范围内， 企业的规模报酬是递增的，企业扩大规模便 有利可图；超过一定规模范围后，企业的规模 报酬便转而递减，扩大规模便得不偿失。
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微观经济学课件平狄克版课件
Chapter 1
13
经济制度
■ 计划经济制度：政府公共部门决策 ■ 市场经济制度：私人部门决策 ■ 混合经济
Chapter 1
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制度与激励
■ 不同的制度产生不同的激励，进而决定人的选 择行为，最终对经济效率产生重大影响 ■ 例子：大学寝室分面条的故事
Chapter 1
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1.1.2 价格和市场
■ 经济个体所有的选择都是在他们面临的 价格基础上作出的。 ■ 价格是由买者和买者在市场中相互作用 决定的。 ■ 市场是通过相互作用决定一种或一系列 商品价格的买卖双方的集合。
Chapter 1
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1.2 经济学的研究方法
■ 理论和模型 ■ 均衡分析和边际分析 ■ 静态、比较静态和动态分析 ■ 实证分析和规范分析
■ 为谁生产：生产出来的巧克力或汽车是分给你 多些还是分给我多些？
Chapter 1
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资源利用的基本问题
■ 为什么资源得不到充分利用？（充分就业）
■ 对给定的资源，为什么产量时高时低？（经济 波动）
■ 货币购买力的变动对汽车和巧克力的生产有什 么影响？（通货膨胀）
■ 在给定的资源条件下，如何使社会总产出越来 越多？（经济增长、技术进步、资本积累、制度 ）
第1章 绪论
Chapter 1
1
本章要点
■ 微观经济学的研究主题 ■ 经济学的研究方法 ■ 市场与市场价格 ■ 名义价格与实际价格 ■ 为什么要学习微观经济学
Chapter 1
2
经济学的主题
■ 经济学？经济学的两个主要分支：微观经济学 和宏观经济学。
■ 微观经济学研究单个经济个体(消费者、劳动 者、资金所有者、土地所有者、企业)的行为及 其相互作用(形成市场)。
平狄克微观经济学(英文版)4
CHAPTER 4INDIVIDUAL AND MARKET DEMANDChapter 4 relies on two important ideas from Chapter 3: the influence of price and income changes on the budget line, and how to determine the optimal consumer choice. The chapter focuses on deriving individual demand graphically by changing either price or income, determining the income and substitution effects of a price change, deriving market demand, demand elasticity, and consumer surplus. These concepts are crucial to understanding the application of demand and supply analysis in Chapter 9 as well as the discussion of market failure in Parts III and IV. The analytical tools students learn in this chapter will be important for the discussion of factor supply and demand in Chapter 14.When discussing the derivation of demand, review how the budget curve pivots around an intercept as price changes and how optimal quantities change as the budget line pivots. Once students understand the effect of price changes on consumer choice, they can grasp the derivation of the price consumption path and the individual demand curve. Remind students that the price a consumer is willing to pay is a measure of the marginal benefit of consuming another unit.Income and substitution effects are often difficult for the student to understand, and they frequently have trouble remembering which effect is which on the graph. Emphasize that the substitution effect explains the portion of the change in demand caused by the change in relative prices (a pivot of the budget line) and the income effect explains the portion of the change in demand caused by a change in purchasing power (a shift of the budget line). The distinction between normal and inferior goods is used to determine the direction of the income effect. You might point out that the demand curve can only slope upwards if the good is inferior and the income effect is unusually large (a Giffen good). Doing a lot of examples is helpful. You might even skip the topic altogether if you are not prepared to devote some time to it. The labor leisure choice problem and derivation of the labor supply curve is a good illustration of income and substitution effects (see Chapter 14).When covering the aggregation of individual demand curves, stress that this is equivalent to the summation of the individual demand curves horizontally. To obtain the market demand curve, you must have demand written in the form Q=f(P) as opposed to the inverse demand P=f(Q). The concept of a kink in the market demand curve is often new to students. Emphasize that this is because not all consumers are in the market at all prices.The concept of elasticity is reintroduced and expanded upon. In particular, the relationship between elasticity and revenue, and arc versus point elasticity is explained. Many students find elasticity to be a mysterious and puzzling concept. Point out that it is merely a more precise measure than the slope of the curve to measure the response of quantity demanded to a change in price, because it is a unit free measure. One effective teaching method is to use a linear demand curve to show that while the slope is constant, the elasticity changes throughout the range of prices. The text relies on this relationship in the discussion of the monopolist’s determination of the profit-maximizing quantity in Chapter 10.Although this chapter introduces consumer surplus, it is not extensively discussed until Chapter 9; producer surplus is covered in Chapter 8. If you introduce it here, it may be necessary to review it again when you get to Chapter 9.Finally, there are other special topics in this chapter and its Appendix that you might cover, time and interest permitting. An application of network externalities is given in Example 4.6. The first part of Section 4.6, “Empirical Estimation of Demand,” is straightforward, particularly if you have covered the forecasting section of Chapter 2. However, the last part, “The Form of the Demand Relationship,” is difficult for students who do not understand logarithms. The Appen dix is intended for students with a background in calculus, and contains a brief mathematical treatment of demand theory.1.How is an individual demand curve different from a market demand curve? Which curve is likely to be more price elastic? (Hint: Assume that there are no network externalities.) The market demand curve is the horizontal summation of the individual demandcurves. The graph of market demand shows the relation between each price and thesum of individual quantities. Because price elasticities of demand may vary byindividual, the price elasticity of demand is likely to be greater than some individualprice elasticities and less than others.2.Is the demand for a particular brand of product, such as Head skis, likely to be more price elastic or price inelastic than the demand for the aggregate of all brands, such as downhill skis? Explain.Individual brands compete with other brands. If the two brands are similar, a smallchange in the price of one good will encourage many consumers to switch to the otherbrand. Because substitutes are readily available, the quantity response to a change inone brand’s price is more elastic than the quantity response for all brands. Thus, thedemand for Head skis is more elastic than the demand for downhill skis.3.Tickets to a rock concert sell for $10. But at that price, the demand is substantially greater than the available number of tickets. Is the value or marginal benefit of an additional ticket greater than, less than, or equal to $10? How might you determine that value?If, at $10, demand exceeds supply, then consumers are willing to bid up the marketprice to a level where the quantity demanded is equal to the quantity supplied. Sinceutility-maximizing consumers must be willing to pay more than $10, then the marginalincrease in satisfaction (value) is greater than $10. One way to determine the value oftickets would be to auction off a block of tickets. The highest bid would determine thevalue of the tickets.4.Suppose a person allocates a given budget between two goods, food and clothing. If food is an inferior good, can you tell whether clothing is inferior or normal? Explain.If an individual consumes only food and clothing, then any increase in income must bespent on either food or clothing (Hint: we assume there are no savings). If food is aninferior good, then, as income increases, consumption falls. With constant prices, theextra income not spent on food must be spent on clothing. Therefore, as incomeincreases, more is spent on clothing, i.e. clothing is a normal good.5. Which of the following combinations of goods are complements and which are substitutes? Could they be either in different circumstances? Discuss.a. a mathematics class and an economics classIf the math class and the economics class do not conflict in scheduling, then the classescould be either complements or substitutes. The math class may illuminate economics,and the economics class can motivate mathematics. If the classes conflict, they aresubstitutes.b. tennis balls and a tennis racketTennis balls and a tennis racket are both needed to play a game of tennis, thus they arecomplements.c. steak and lobsterFoods can both complement and substitute for each other. Steak and lobster cancompete, i.e., be substitutes, when they are listed as separate items on a menu.However, they can also function as complements because they are often served together.d. a plane trip and a train trip to the same destinationTwo modes of transportation between the same two points are substitutes for oneanother.e. bacon and eggsBacon and eggs are often eaten together and are, therefore, complementary goods. Byconsidering them in relation to something else, such as pancakes, bacon and eggs canfunction as substitutes.6.Which of the following events would cause a movement along the demand curve for U.S.-produced clothing, and which would cause a shift in the demand curve?a. the removal of quotas on the importation of foreign clothesThe removal of quotas will shift the demand curve inward for domestically-producedclothes, because foreign-produced goods are substitutes for domestically-produced goods.Both the equilibrium price and quantity will fall as foreign clothes are traded in a freemarket environment.b. an increase in the income of U.S. citizensWhen income rises, expenditures on normal goods such as clothing increase, causingthe demand curve to shift out. The equilibrium quantity and price will increase.c. a cut in the indu stry’s costs of producing domestic clothes that is passed on to themarket in the form of lower clothing pricesA cut in an industry’s costs will shift the supply curve out. The equilibrium price willfall and quantity will increase. There is a movement along the demand curve.7. For which of the following goods is a price increase likely to lead to a substantial income (as well as substitution) effect?a. saltSmall income effect, small substitution effect: The amount of income that is spent onsalt is relatively small, but since there are few substitutes for salt, consumers will notreadily substitute away from it. As the price of salt rises, real income will fall onlyslightly, thus leading to a small decline in consumption.b. housingLarge income effect, no substitution effect: The amount of income spent on housing isrelatively large for most consumers. If the price of housing were to rise, real incomewould be reduced substantially, thereby reducing the consumption of all other goods.However, consumers would find it impossible to substitute for housing, in general.c. theater ticketsSmall income effect, large substitution effect: The amount of income that is spent ontheater tickets is relatively small, but consumers can substitute away from the theatertickets by choosing other forms of entertainment (e.g., television and movies). As theprice of theater tickets rises, real income will fall only slightly, thus leading to a smalldecline in consumption.d. foodLarge income effect, no substitution effect: As with housing, the amount of income spenton food is relatively large for most consumers. Price increases for food will reduce realincome substantially, thereby reducing the consumption of all other commodities.Although consumers can substitute out of particular foods, they cannot substitute out offood in general.8. Suppose that the average household in a state consumes 500 gallons of gasoline per year.A 10-cent gasoline tax is introduced, coupled with a $50 annual tax rebate per household. Will the household be better or worse off after the new program is introduced?If the household does not change its consumption of gasoline, it will be unaffected bythe tax-rebate program, because in this case the household pays 0.10*500=$50 in taxesand receives $50 as an annual tax rebate. The two effects would cancel each other out.To the extent that the household reduces its gas consumption through substitution, itmust be better off. The new budget line (price change plus rebate) will pass throughthe old consumption point of 500 gallons of gasoline, and any now affordable bundlewhich contains less gasoline must be on a higher indifference curve. The household willnot choose any bundle with more gasoline because these bundles are all inside the oldbudget line, and hence are inferior to the bundle with 500 gallons of gas.9. Which of the following three groups is likely to have the most, and which the least, price-elastic demand for membership in the Association of Business Economists?a. studentsThe major difference among the groups is the level of income. We know that if theconsumption of a good constitutes a large percentage of an individual’s income, then thedemand for the good will be relatively elastic. If we assume that a membership in theAssociation of Business Economists is likely to be a large expenditure for students, wemay conclude that the demand will be relatively elastic for this group.b. junior executivesThe level of income for junior executives will be larger than that of students, butsmaller than that of senior executives. Therefore, the demand for a membership forthis group will be less elastic than that of the students but more elastic than that of thesenior executives.c. senior executivesThe high earnings among senior executives will result in a relatively inelastic demandfor membership.1. The ACME corporation determines that at current prices the demand for its computer chips has a price elasticity of -2 in the short run, while the price elasticity for its disk drives is -1.a. If the corporation decides to raise the price of both products by 10 percent, what willhappen to its sales? To its sales revenue?We know the formula for the elasticity of demand is:E Q PP =%%∆∆. For computer chips, E P = -2, so a 10 percent increase in price will reduce the quantitysold by 20 percent. For disk drives, E P = -1, so a 10 percent increase in price willreduce sales by 10 percent.Sales revenue is equal to price times quantity sold. Let TR 1 = P 1Q 1 be revenue beforethe price change and TR 2 = P 2Q 2 be revenue after the price change.For computer chips:∆TR cc = P 2Q 2 - P 1Q 1∆TR cc = (1.1P 1 )(0.8Q 1 ) - P 1Q 1 = -0.12P 1Q 1, or a 12 percent decline.For disk drives:∆TR dd = P 2Q 2 - P 1Q 1∆TR dd = (1.1P 1 )(0.9Q 1 ) - P 1Q 1 = -0.01P 1Q 1, or a 1 percent decline.Therefore, sales revenue from computer chips decreases substantially, -12 percent,while the sales revenue from disk drives is almost unchanged, -1 percent. Note that atthe point on the demand curve where demand is unit elastic, total revenue ismaximized.b. Can you tell from the available information which product will generate the mostrevenue for the firm? If yes, why? If not, what additional information would you need?No. Although we know the responsiveness of demand to changes in price, we need toknow both quantities and prices of the products to determine total sales revenue.2. Refer to Example 4.3 on the aggregate demand for wheat in 1998. Consider 1996, at which time the domestic demand curve was Q DD = 1560 - 60P . The export demand curve, however, was about the same as in 1998, i.e., Q DE =1544-176P . Calculate and draw the aggregate demand curve for wheat in 1996.Given the domestic demand curve for wheat is Q DD = 1560-60P, we find an intercept of1560 on the quantity axis and an intercept of156060=26 on the price axis. The export demand curve for wheat, Q DE = 1544 - 176P, has an intercept of 1544 on the quantityaxis and an intercept of 1544176=8.77 on the price axis. The total demand curve follows the domestic demand curve between the prices of $26 and $8.77 because the exportdemand is 0 in this range of prices. At $8.77 and a quantity of approximately 1033.7 =1560 - (60)(8.77), the total demand curve kinks. As price drops below $8.77, totaldemand is domestic demand plus export demand, which is the horizontal sum of thetwo individual demand curves. Between a price of $26 and $8.77 the equation for totaldemand is Q T =1560-60P and between a price of $8.77 and zero, the equation for totaldemand is Q T =Q DD +Q DE=3104-236P. See figure 4.2. 268.771560Q PFigure 4.23. Judy has decided to allocate exactly $500 to textbooks at college every year, even though she knows that the prices are likely to increase by 5 to 10 percent per year and that she will be getting a substantial monetary gift from her grandparents next year. What is Judy’s price elasticity of demand for textbooks? Income elasticity?Price elasticity of demand is percentage change in quantity for a given percentagechange in price. Judy knows that prices will go up in the future. Given she is going tospend a fixed amount on books, this must mean that her quantity demanded willdecrease as price increases. Since expenditure is constant the percentage change inquantity demanded must be equal to the percentage change in price, and priceelasticity is -1. Income elasticity must be zero because although she expects a largemonetary gift, she has no plans to purchase more books. Recall that income elasticity isdefined as the percentage change in quantity demanded for a given percentage changein income, all else the same.4. Vera has decided to upgrade the operating system on her new PC. She hears that the new Linux operating system is technologically superior to the Windows operating system and substantially lower in price. However, when she asks her friends it turns out they all use PCs with Windows. They agree that Linux is more appealing but add that they see relatively few copies of Linux on sale at the local retail software stores. Based on what she learns and observes, Vera chooses to upgrade her PC with Windows. Can you explain her decision?Vera is consuming under the influence of a positive network externality (not abandwagon effect). When she hears that there are limited software choices that arecompatible with the Linux operating system, she decides to go with Windows. If shehad not been interested in acquiring much software, she may have gone with Linux.See Example 4.6 in the text. In the future, however, there may be a bandwagon effect,i.e., the purchase of Linux because almost everyone else has it. As more people useLinux, manufacturers might introduce more software that is compatible with the Linuxoperating system. As the Linux based software section at the local computer store getslarger and larger, this prompts more consumers to purchase Linux. Eventually, theWindows section shrinks as the Linux section becomes larger and larger.5. Suppose you are in charge of a toll bridge that is essentially cost free. The demand for bridge crossings Q is given by P = 12 - 2Q.a. Draw the demand curve for bridge crossings.See figure 5.4a below.b. How many people would cross the bridge if there were no toll?At a price of zero, the quantity demanded would be 6.c. What is the loss of consumer surplus associated with the charge of a bridge toll of $6?The consumer surplus with no toll is equal to (0.5)(6)(12) = 36. Consumer surplus witha $6 toll is equal to (0.5)(3)(6) = 9, illustrated in Figure 4.4.a. Therefore, the loss ofconsumer surplus is $27.Figure 4.6.a.iAssuming that the price of orange juice is less than the price of apple juice, the consumer will maximize her utility by consuming only orange juice. As the level of income varies, only the amount of orange juice varies. Thus, the income consumption cur ve will be the “orange juice axis” in Figure 4.6.a.ii.IncomeFigure 4.7.b8. You are managing a $300,000 city budget in which monies are spent on schools and public safety only. You are about to receive aid from the federal government to support a special anti-drug law enforcement program. Two programs that are available are (1) a $100,000 grant that must be spent on law enforcement; and (2) a 100 percent matching grant, in which each dollar of local spending on law enforcement is matched by a dollar of federal money. The federal matching program limits its payment to each city to a maximum of $100,000.a. Complete the table below with the amounts available for safety.SCHOOLS SAFETYNo Govt.AssistanceSAFETYProgram (1)SAFETYProgram (2)$50,000$100,000$150,000$200,000$250,000$300,000 a. See Table 4.8.a.SCHOOLS SAFETYNo Govt.AssistanceSAFETYProgram (1)SAFETYProgram (2)$0 $300,000 $400,000 $400,000 $50,000 $250,000 $350,000 $350,000 $100,000 $200,000 $300,000 $300,000inferior). If you cannot determine the income elasticity, what additional information might you need?a. Bill spends all his income on books and coffee. He finds $20 while rummagingthrough a used paperback bin at the bookstore. He immediately buys a new hardcover book of poetry.Books are a normal good since his consumption of books increases with income. Coffeeis a normal or neutral good since consumption of coffee did not fall when incomeincreased.b. Bill loses $10 he was going to use to buy a double espresso. He decides to sell hisnew book at a discount to his friend and use the money to buy coffee.Coffee is clearly a normal good.c. Being bohemian becomes the latest teen fad. As a result, coffee and book prices riseby 25 percent. Bill lowers his consumption of both goods by the same percentage.Books and coffee are both normal goods since his response to a decline in real income isto decrease consumption of both goods.d. Bill drops out of art school and gets an M.B.A. instead. He stops reading books anddrinking coffee. Now he reads The Wall Street Journal and drinks bottled mineral water.His tastes have changed completely, and we do not know why. We could use moreinformation regarding his level of income, his desire for sleep, and maybe even a changein political affiliation.10. Suppose the income elasticity of demand for food is 0.5, and the price elasticity of demand is -1.0. Suppose also that Felicia spends $10,000 a year on food, and that the price of food is $2 and her income is $25,000.a. If a $2 sales tax on food were to cause the price of food to double, what would happento her consumption of food? (Hint: Since a large price change is involved, you should assume that the price elasticity measures an arc elasticity, rather than a point elasticity.)The price of food doubles from $2 to $4, so arc elasticity should be used:E P =∆Q∆P⎛⎝⎫⎭P1+P22Q1+Q22⎛⎝⎫⎭⎪⎪⎪.We know that EP= -1, P= 2, ∆P= 2, and Q=5000. We also know that Q2, the new quantity, is Q+∆Q. Thus, if there is no change in income, we may solve for ∆Q:-1=∆Q2⎛⎝⎫⎭2+425,000+5,000+∆Q()2⎛⎝⎫⎭⎪⎪⎪.By cross-multiplying and rearranging terms, we find that ∆Q = -2,500. This means thatshe decreases her consumption of food from 5,000 to 2,500 units.b. Suppose that she is given a tax rebate of $5,000 to ease the effect of the tax. Whatwould her consumption of food be now?A tax rebate of $5,000 implies an income increase of $5,000. To calculate the responseof demand to the tax rebate, use the definition of the arc elasticity of income.E I =∆Q∆I⎛⎝⎫⎭I1+I22Q1+Q22⎛⎝⎫⎭⎪⎪⎪.We know that EI= 0.5, I= 25,000, ∆I= 5,000,Q= 2,500 (from the answer to 10.a). Assuming no change in price, we solve for ∆Q.0.5=∆Q5,000⎛⎝⎫⎭ ⎪25,000+30,00022,500+2,500+∆Q()2⎛⎝⎫⎭⎪⎪⎪.By cross-multiplying and rearranging terms, we find that ∆Q= 238 (approximately).This means that she increases her consumption of food from 2,500 to 2,738 units.c. Is she better or worse off when given a rebate equal to the sales tax payments?Discuss.We want to know if her original indifference curve lies above or below her finalindifference curve after the sales tax and after the tax rebate. On her final indifferencecurve, she chooses to consume 2,738 units of food (for $10,952) and $19,048 of othergoods. Was this combination attainable with her original budget? At the original foodprice of $2, this combination would have cost her (2,738)($2) + $19,048 = $24,524, thusleaving her an extra $476 to spend on either food or other consumption. Therefore, shewould have been better off before the sales tax and tax rebate. She could havepurchased more of both food and other goods than she could have after the taxes.11. Suppose that you are the consultant to an agricultural cooperative that is deciding whether members should cut their production of cotton in half next year. The cooperative wan ts your advice as to whether this will increase the farmers’ revenues. Knowing that cotton (C) and watermelons (W) both compete for agricultural land in the South, you estimate the demand for cotton to be:C=3.5-1.0P C+0.25P W+0.50I,where P C is the price of cotton, P W the price of watermelon, and I income. Should you support or oppose the plan? Is there any additional information that would help you to provide a definitive answer?If production of cotton is cut in half, then the price of cotton will increase, given that wesee from the equation above that demand is downward sloping. With price increasingand quantity demanded decreasing, revenue could go either way. It depends onwhether demand is inelastic or elastic at the current price. If demand is inelastic thena decrease in production and an increase in price could increase revenue. If demand iselastic then a decrease in production and an increase in price will clearly decreaserevenue. You need to know the current price and/or quantity demanded to figure outthe current level of elasticity.。