ChoiceUnderUncertainty(微观经济学-华侨大学,Jef
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ofCompetitiveMarkets(微观经济学-华侨大学,Jeff
Price
10
7
5
Producer Surplus
Consumer Surplus
0
Chapter 1Consumer A
Consumer B
Q0
Consumer C
S
Between 0 and Q0 consumers A and B receive a net gain from buying the product-consumer surplus
(A - B) + (-A - C) = -B - C
The deadweight loss is the inefficiency of the price controls or the loss of the producer surplus exceeds the gain from consumer surplus.
the deadweight loss.
D
Q1
Q0
Q2
Quantity
7
Change in Consumer and Producer Surplus from Price Controls
Observations:
The total loss is equal to area B + C.
The total change in surplus =
Chapter 1
20
Welfare Loss When Price Is Held Below Market-Clearing Level
Price
B
P0
A
C
P1
Chapter 1
Q1
Q0
S
When price is regulated to be no higher than P1, the deadweight loss given by triangles B and C results.
Ch12Uncertainty(中级微观经济学-清华大学,钟笑寒)
State-Contingent Budget Constraints
Buy
$K of accident insurance. Cna = m - K. Ca = m - L - K + K = m - L + (1- )K. So K = (Ca - m + L)/(1- ) And Cna = m - (Ca - m + L)/(1- )
Contingent Consumption
Q:
What is the consumption bundle that is being chosen under uncertainty? A: Contingent consumption plan. A specification of what will be consumed in each different state of nature. – Contingent: dependent on something uncertain or in the future.
State-Contingent Budget Constraints
Buy
$K of accident insurance. Cna = m - K. Ca = m - L - K + K = m - L + (1- )K. So K = (Ca - m + L)/(1- ) And Cna = m - (Ca - m + L)/(1- ) m L I.e. Cna Ca 1 1
Expected Utility
Q:
What is the utility when state 1 or 2 is certain? A: u(c1) or u(c2). Implications.The expected utility is a probability-weighted sum of utility in each state. (often be denoted as Eu.)
ChoiceUnderUncertainty(微观经济学-华侨大学,Jef
Chapter 5
Slide 11
Describing Risk
Given:
Two possible outcomes having payoffs X1 and X2
Probabilities of each outcome is given by Pr1 & Pr2
Chapter 5
The first job is based entirely on commission.
The second is a salaried position.
Chapter 5
Slide 15
Describing Risk
Variability
A Scenario
There are two equally likely outcomes in the first job--$2,000 for a good sales job and $1,000 for a modestly successful one.
Greater variability from expected values signals greater risk.
Deviation
Difference between expected payoff and actual payoff
Chapter 5
Slide 19
Describing Risk
Chapter 5
Slide 21
Describing Risk
Variability
The standard deviation is written:
Pr1 X 1 E ( X )2 Pr2 X 2 E ( X )2
中级微观经济学课件 (1)
E U 1U (c1) 2U (c2 )
dE U 1M U (c1)dc1 2M U (c2 )dc2
不确定条件下的偏好 （Preferences Under Uncertainty）
E U 1U (c1) 2U (c2 ) dE U 1M U (c1)dc1 2M U (c2 )dc2 dE U 0 1M U (c1)dc1 2M U (c2 )dc2 0
不确定条件下的偏好 （Preferences Under Uncertainty）
u 三种对待风险的态度： 厌恶风险（risk-aversion）. 偏好风险（risk-loving）. 风险中性（risk-neutrality）.
（例子：课后作业第3-5题）
不确定条件下的偏好 （Preferences Under Uncertainty）
U， > 0, U” >0 。即效用函 数是凸函数。
$0
$45
$90
Wealth
不确定条件下的偏好 （Preferences Under Uncertainty）
12
EU=7
2
$0
$45
$90
Wealth
不确定条件下的偏好 （Preferences Under Uncertainty）
U($45) = EU 风险中性. 12
12
EU=7
2
$0
$45
$90
Wealth
不确定条件下的偏好 （Preferences Under Uncertainty）
12
EU=7 U($45)
2
U($45) < EU 风险偏好. 确定性结果45美元的效用大于 0美元和90美元两种状态的效用 的期望值。即，期望值的效用
dE U 1M U (c1)dc1 2M U (c2 )dc2
不确定条件下的偏好 （Preferences Under Uncertainty）
E U 1U (c1) 2U (c2 ) dE U 1M U (c1)dc1 2M U (c2 )dc2 dE U 0 1M U (c1)dc1 2M U (c2 )dc2 0
不确定条件下的偏好 （Preferences Under Uncertainty）
u 三种对待风险的态度： 厌恶风险（risk-aversion）. 偏好风险（risk-loving）. 风险中性（risk-neutrality）.
（例子：课后作业第3-5题）
不确定条件下的偏好 （Preferences Under Uncertainty）
U， > 0, U” >0 。即效用函 数是凸函数。
$0
$45
$90
Wealth
不确定条件下的偏好 （Preferences Under Uncertainty）
12
EU=7
2
$0
$45
$90
Wealth
不确定条件下的偏好 （Preferences Under Uncertainty）
U($45) = EU 风险中性. 12
12
EU=7
2
$0
$45
$90
Wealth
不确定条件下的偏好 （Preferences Under Uncertainty）
12
EU=7 U($45)
2
U($45) < EU 风险偏好. 确定性结果45美元的效用大于 0美元和90美元两种状态的效用 的期望值。即，期望值的效用
华侨大学 微观经济学 2017年博士研究生考博真题
（1）要使效用最大，该购买的X和Y各为多少？
（2）假如X的价格提高44%，Y的价格不变，为保持原有的效用水平，收入必须增加多少？
共1页第1页
华侨大学72017年博士研究生入学考试专业课试卷答案必须写在答题纸上招生专业企业管理科目名称微观经济学科目代码一论述题共计90分1试用图说明需求价格弹性与总收益之间的关系及厂商扩大总收益的价格策略
华侨大学2017年博士研究生入学考ห้องสมุดไป่ตู้专业课试卷
（答案必须写在答题纸上）
招生专业企业管理科目名称微观经济学科目代码
1、论述题（共计90分）
1试用图说明需求价格弹性与总收益之间的关系，及厂商扩大总收益的价格策略。
2试述外部影响如何导致资源配置失当。
3试论述现代西方主流经济学流派的渊源。
4试用微观经济学若干理论分析我国住房价格问题及其解决办法。
5论述可持续发展与城市阶梯水价。
2、计算题（共计10分）
1已知某人每天收入120元，全部用于购买商品X和Y，其效用函数为U=XY，PX=2元，PY=3元。
（2）假如X的价格提高44%，Y的价格不变，为保持原有的效用水平，收入必须增加多少？
共1页第1页
华侨大学72017年博士研究生入学考试专业课试卷答案必须写在答题纸上招生专业企业管理科目名称微观经济学科目代码一论述题共计90分1试用图说明需求价格弹性与总收益之间的关系及厂商扩大总收益的价格策略
华侨大学2017年博士研究生入学考ห้องสมุดไป่ตู้专业课试卷
（答案必须写在答题纸上）
招生专业企业管理科目名称微观经济学科目代码
1、论述题（共计90分）
1试用图说明需求价格弹性与总收益之间的关系，及厂商扩大总收益的价格策略。
2试述外部影响如何导致资源配置失当。
3试论述现代西方主流经济学流派的渊源。
4试用微观经济学若干理论分析我国住房价格问题及其解决办法。
5论述可持续发展与城市阶梯水价。
2、计算题（共计10分）
1已知某人每天收入120元，全部用于购买商品X和Y，其效用函数为U=XY，PX=2元，PY=3元。
ofCompetitiveMarkets(微观经济学-华侨大学,Jeff
The total change in surplus =
(A - B) + (-A - C) = -B - C
The deadweight loss is the inefficiency of the price controls or the loss of the producer surplus exceeds the gain from consumer surplus.
Producer surplus is the total benefit or revenue that producers receive beyond what it cost to produce a good.
Chapter 1
Slide 4
Consumer and Producer Surplus
Price
10
7
5
Producer Surplus
Consumer Surplus
0
Consumer A
Consumer B
Q0
Consumer C
S
Between 0 and Q0 consumers A and B receive a net gain from buying the product-consumer surplus
the deadweight loss.
D
Q1
Q0
Q2
Quantity
Slide 7
Change in Consumer and Producer Surplus from Price Controls
Observations:
The total loss is equal to area B + C.
(A - B) + (-A - C) = -B - C
The deadweight loss is the inefficiency of the price controls or the loss of the producer surplus exceeds the gain from consumer surplus.
Producer surplus is the total benefit or revenue that producers receive beyond what it cost to produce a good.
Chapter 1
Slide 4
Consumer and Producer Surplus
Price
10
7
5
Producer Surplus
Consumer Surplus
0
Consumer A
Consumer B
Q0
Consumer C
S
Between 0 and Q0 consumers A and B receive a net gain from buying the product-consumer surplus
the deadweight loss.
D
Q1
Q0
Q2
Quantity
Slide 7
Change in Consumer and Producer Surplus from Price Controls
Observations:
The total loss is equal to area B + C.
微观经济学-清华大学课件Ch5Choice消费者最优选择
x2 MRS = -1
x*2 0
Slope = -p1/p2 with p1 < p2.
x
* 1
y p1
x1
Examples of Corner Solutions --
the Perfect Substitutes Case
So when U(x1,x2) = x1 + x2, the most
If buying (x1*,x2*) costs $m then the budget is exhausted.
Rational Constrained Choice
x2
(x1*,x2*) is interior.
(a) (x1*,x2*) exhausts the
budget; p1x1* + p2x2* = m.
x1*
x1
Rational Constrained Choice
(x1*,x2*) satisfies two conditions: (a) the budget is exhausted;
p1x1* + p2x2* = m (b) the slope of the budget constraint,
x2
y
MRS1/p2 with p1 = p2.
y
x1
p1
Examples of Corner Solutions -the Perfect Substitutes Case
x2
y
All the bundles in the
p2
constraint are equally the
At
(x1*,x2*),
a b
x*2 0
Slope = -p1/p2 with p1 < p2.
x
* 1
y p1
x1
Examples of Corner Solutions --
the Perfect Substitutes Case
So when U(x1,x2) = x1 + x2, the most
If buying (x1*,x2*) costs $m then the budget is exhausted.
Rational Constrained Choice
x2
(x1*,x2*) is interior.
(a) (x1*,x2*) exhausts the
budget; p1x1* + p2x2* = m.
x1*
x1
Rational Constrained Choice
(x1*,x2*) satisfies two conditions: (a) the budget is exhausted;
p1x1* + p2x2* = m (b) the slope of the budget constraint,
x2
y
MRS1/p2 with p1 = p2.
y
x1
p1
Examples of Corner Solutions -the Perfect Substitutes Case
x2
y
All the bundles in the
p2
constraint are equally the
At
(x1*,x2*),
a b
《微观经济学》清华大学课件Ch5Choice消费者最优选择共37页文档
(x1*,x2*) also exhausts the budget so
p1x* 1p2x* 2m . (B)
Computing Ordinary Demands a Cobb-Douglas Example.
So we have discovered that the most preferred affordable bundle for a consumer with Cobb-Douglas preferences
x2
(x1*,x2*) is interior.
(a) (x1*,x2*) exhausts the
budget; p1x1* + p2x2* = m.
x2*
x1*
x1
Rational Constrained Choice
x2
(x1*,x2*) is interior .
(b) The slope of the indiff.
U (x1,x2)x1 axb 2
is
( ) (x * 1 ,x * 2 )(a a m b )p 1 ,(a b m b )p 2.
Computing Ordinary Demands -
a Cobb-Douglas Example.
x2
U (x1,x2)x1 axb 2
x
* 2
bm
(a b )p 2
curve at (x1*,x2*) equals the slope of the budget
constraint. x2*
x1*
x1
Rational Constrained Choice
(x1*,x2*) satisfies two conditions: (a) the budget is exhausted;
p1x* 1p2x* 2m . (B)
Computing Ordinary Demands a Cobb-Douglas Example.
So we have discovered that the most preferred affordable bundle for a consumer with Cobb-Douglas preferences
x2
(x1*,x2*) is interior.
(a) (x1*,x2*) exhausts the
budget; p1x1* + p2x2* = m.
x2*
x1*
x1
Rational Constrained Choice
x2
(x1*,x2*) is interior .
(b) The slope of the indiff.
U (x1,x2)x1 axb 2
is
( ) (x * 1 ,x * 2 )(a a m b )p 1 ,(a b m b )p 2.
Computing Ordinary Demands -
a Cobb-Douglas Example.
x2
U (x1,x2)x1 axb 2
x
* 2
bm
(a b )p 2
curve at (x1*,x2*) equals the slope of the budget
constraint. x2*
x1*
x1
Rational Constrained Choice
(x1*,x2*) satisfies two conditions: (a) the budget is exhausted;
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Expected Value
The weighted average of the payoffs or values resulting from all possible outcomes.
The probabilities of each outcome are used as weights
Generally, expected value is written as:
E(X) Pr1X1 Pr2X 2 ... Prn X n
Chapter 5
Slide 13
Describing Risk
Variability
The extent to which possible outcomes of an uncertain even may differ
The first job is based entirely on commission.
The second is a salaried position.
Chapter 5
Slide 15
Describing Risk
Variability
A Scenario
There are two equally likely outcomes in the first job--$2,000 for a good sales job and $1,000 for a modestly successful one.
Objective Interpretation Based on the observed frequency of past events
Chapter 5
Slide 6
Describing Risk
Interpreting Probability
Subjective Based on perception or experience with or without an observed frequency
Chapter 5
Slide 4
Describing Risk
Interpreting Probability
The likelihood that a given outcome will occur
Chapter 5
Slide 5
Describing Risk
Interpreting Probability
Different information or different abilities to process the same information can influence the subjective probability
Chapter 5
Slide 7
Describing Risk
Objective Probability 100 explorations, 25 successes and 75 failures Probability (Pr) of success = 1/4 and the probability of failure = 3/4
Chapter 5
Slide 10
Chapter 5
Choice Under Uncertainty
Topics to be Discussed
Describing Risk Preferences Toward Risk Reducing Risk The Demand for Risky Assets
Chapter 5
Expected value measures the central tendency; the payoff or value expected on average
Chapter 5
Slide 8
Describing Risk
An Example
Investment in offshore drilling exploration: Two outcomes are possible
Slide 11
Describing Risk
Given:
Two possible outcomes having payoffs X1 and X2
Probabilities of each outcome is given by Pr1 & Pr2
Chapter 5
Slide 12
Describing Risk
Slide 2
Introduction
Choice with certainty is reasonably straightforward.
How do we choose when certain variables such as income and prices are uncertain (i.e. making choices with risk)?
Chapter bing Risk
To measure risk we must know: 1) All of the possible outcomes. 2) The likelihood that each outcome will occur (its probability).
Success -- the stock price increase from $30 to $40/share
Failure -- the stock price falls from $30 to $20/share
Chapter 5
Slide 9
Describing Risk
An Example
Chapter 5
Slide 14
Describing Risk
Variability
A Scenario
Suppose you are choosing between two part-time sales jobs that have the same expected income ($1,500)
Describing Risk
Expected Value (EV)
An Example:
EV Pr(success)($40/share)Pr(failure)($20/share)
EV 1 4($40/share ) 3 4($20/share )
EV $25/share
Chapter 5