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2. BLM
TKETC TERCHLER
(Consumer Preferences)
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Amalarmz
Tketici tercihini aklamak Fayda Kavraman aklamak Fiyat ve gelirin nemi Optimal davran Tketici dengesi
Anahtar kavramlar: Homo-economicus, faydafonksiyonu, farkszlk erileri, marjinal ikameoran, bte Kst, tketici dengesi, gelir ikameetkisi, bireysel talep fonksiyonu
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htiya ve Tketici Tercihleri /Kavramlar
htita: Karlandnda insanlara haz,karlanmadnda ise elem, ve doyumsuzlukveren duygudur (alk ve susuzluk gibi)
Mal: nsan ihtiyalarn karlayan her trl fizikivarlk ve hizmetlerdir.
Tketici: Mal tketerek ihtiyalarn karlayankimsedir.
Fayda: Mallarn ihtiyalar giderme zelliidir.
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ktisadiAklclk ve Homo-Economicus
1. Tam bilgiye sahip olma,
2. Seici olma,
3. ou aza tercih etme,4. Tercihler arasnda tutarl olma.
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Fayda Kavram
Mallarn ihtiyalarn giderme zelliidir.
Kardinal ve ordinal yaklam
Fayda llebilir [Jevons (1854) ve Walras(1874)]
Fayda llemez [Edgeworth (1881),Antonelli (1886), rving Fisher (1892)]
Deer paradoksu?
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Fayda Kavram/TU and MU
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FaydaFonksiyonu
There are three steps involved in thestudy of consumer behavior
1. Consumer Preferences To describe how and why people prefer
one good to another
2. BudgetConstraints
People have limited incomes
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Farkszlk Erileri (IndifferenceCurves:An Example)
Market Basket Units ofFood Units ofClothing
A 20 30
B 10 50
D 40 20
E 30 40
G 10 20
H 10 40
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The consumerprefersA to allcombinationsin the yellow box, while
allthose in the pinkbox are preferredto A.
Farkszlk Erileri (IndifferenceCurves:An Example)
Food
10
20
30
40
10 20 30 40
Clothing
50
G
A
EH
B
D
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Indifferentbetween pointsB, A, & D
E is preferredto points on U1Pointson U1are preferred toH & G
Farkszlk Erileri(Indifference Curves:An Example)
Food
10
20
30
40
10 20 30 40
Clothing
50
U1GD
A
EH
B
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Farkszlk Erileri(Indifference Curves)
Farkszlk erisi zerindeki her nokta, eittoplam fayda
Mal dzleminin her noktasnda farkszlkerisi geer
Farkszlk erisi negatiftir
Orjine dbkeydir
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U2
U3
Farkszlk Erileri(Indifference Curves)
Food
Clothing
U1
ABD
Market basketAis preferred to B.Market basket B is
preferred to D.
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Farkszlk Erileri(Indifference Curves)
Food
Clothing B is preferred to DA is indifferent to B & DB must be indifferent to
D but that cant be if B ispreferred to D
U1
U1
U
2
U2
A
B
D
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A
B
D
EG
-1
-6
1
1
-4
-21
1
Observation: The amountof clothing given up for
1 unit of food decreasesfrom 6 to 1
Marjinalkame Oran(Marginal Rate ofSubstitution)
Food
Clothing
2 3 4 51
2
4
6
8
1012
14
16
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Marjinalkame Oran(Marginal Rate ofSubstitution)
Food2 3 4 51
Clothing
2
4
6
8
1012
14
16 A
B
D
EG
-6
1
1
11
-4
-2-1
MRS = 6
MRS = 2
FCMRS(
(!
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Azalan Marjinalkame Oran(Marginal Rate ofSubstitution)
MRS, kaytszlk erisi aa gittikeazalr
Along an indifference curve there is adiminishing marginal rate of substitution(Azalan marjinal kame erisi)
The MRS went from 6 to 4 to 1
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MarjinalFayda ve Tketici TercihiMarginal Utilityand ConsumerChoice
Formally:
C)(MUF)(MU CF ((!0No change in total utility along an indifference curve.Trade off of one good to the other leaves the consumer
just as well off.
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Marginal Utilityand ConsumerChoice
Rearranging:
CF
CF
/MUMUMRS
saycanWe
CforFofMRSFC
SinceMUMUFC
!
!((
!((
/
//
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Marginal Utilityand ConsumerChoice
When consumers maximize satisfaction:
CF/PPMRS !
CFCF// UU !
Since the MRS is also equal to the ratio of themarginal utility of consuming F and C
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Marginal Utilityand ConsumerChoice
Rearranging, gives the equation for utilitymaximization:
CCFFPMUPMU // !
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Marjinalkame Oran(Marginal Rate ofSubstitution)
Two polar cases are of interest Perfect substitutes (MRS sabit)
Perfect complements (MRS=0)
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Tketici Tercihi/Kaytszlk Erisi
Orange Juice(glasses)
AppleJuice
(glasses)
2 3 41
1
2
3
4
0
Mkemmel
kame(Perfect
Substitutes)
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Tketici Tercihi/Kaytszlk Erisi
Right Shoes
LeftShoes
2 3 41
1
2
3
4
0
Mkemmel Tamamlayc(Perfect
Complements)
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Tketici Tercihi( ConsumerPreferences)
These consumersplace a greater
value onperformancethan styling
Styling
Performance
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Tketici Tercihi( ConsumerPreferences
These consumersplace a greater
value on styling thanperformance
Styling
Performance
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Fayda (Utility)
Utility function
Formula that assigns a level of utility to
individual market baskets If the utility function is
U(F,C) = F+ 2CA market basket with 8 units of food and 3 units of
clothing gives a utility of14 = 8 + 2(3)
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Utility - Example
MarketBasket
Food Clothing Utility
A 8 3 8 + 2(3) = 14
B 6 4 6 + 2(4) = 14
C 4 4 4 + 2(4) = 12
Consumer is indifferent between A & B andprefers both to C
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Utility - Example
Baskets for each level of utility can beplotted to get an indifference curve
To find the indifference curve for a utility of14, we can change the combinations of foodand clothing that give us a utility of14
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Utility - Example
Food10 155
5
10
15
0
Clothing
U1 = 25
U2 = 50
U3 = 100A
B
C
Basket U = FCC 25 = 2.5(10)A 25 = 5(5)B 25 = 10(2.5)
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ICPFP CF !
Bte Dorusu (The Budget Line)
The budget line then can be written:
All income is allocated to food (F) and/or clothing(C)
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Bte Dorusu (The Budget Line)
Different choices of food and clothing canbe calculated that use all income
These choices can be graphed as the budgetline
Example: Assume income of $80/week, PF = $1 and PC
= $2
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Bte Kst(Budget Constraints)
MarketBasket
Food
PF = $1
Clothing
PC = $2
IncomeI = PFF + PCC
A 0 40 $80B 20 30 $80
D 40 20 $80
E 60 10 $80
G 80 0 $80
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C
F
P
P
F
CSlope -
2
1- !!
(
(!
Bte Dorusu (The Budget Line)
10
20
A
B
D
E
G
(I/PC) = 40
Food40 60 80 = (I/PF)20
10
20
30
0
Clothing
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Bte Dorusu (The Budget Line)
YXP
P
P
M
YPXPM
YPXPM
Y
X
Y
YX
YX
!
!
!
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Bte Dorusu Deiimi(The Budget Line Changes)
An increase inincome shifts
the budget line
outward
Food(units per week)
Clothing(units
per week)
80 120 16040
20
40
60
80
0
(I = $160)L2
(I = $80)
L1
L3
(I =$40)
A decrease inincome shifts
the budget lineinward
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Fiyat Deiiminin Etkisi(The Effects ofChangesin Prices)
The Effects of Changes in Prices If the price of one good decreases, the
budget line shifts outward, pivoting from the
other goods intercept. If the price of food decreases and you buy
only food (x-intercept), then you can buymore food. The x-intercept shifts out.
If you buy only clothing (y-intercept), you canbuy the same amount. No change in y-intercept.
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Fiyat Deiiminin Etkisi(The Effects ofChangesin Prices)
(PF = 1)
L1
An increase in theprice of food to$2.00 changesthe slope of the
budget line androtates it inward.
L3
(PF= 2)(PF = 1/2)
L2
A decrease in theprice of food to$.50 changes
the slope of thebudget line and
rotates it outward.
40Food(units per week)
Clothing(units
per week)
80 120 160
40
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Fiyat Deiiminin Etkisi /Talepfonk
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Tketici Tercihi (ConsumerChoice)
Given preferences and budgetconstraints, how do consumers choose
what to buy?Consumers choose a combination of
goods that will maximize theirsatisfaction, given the limited budget
available to them
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Tketici Tercihi (ConsumerChoice)
The maximizing market basket mustsatisfy two conditions:
1. It must be located on the budget line They spend all their income more is better
2. It must give the consumer the mostpreferred combination of goods and
services
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Tketici Tercihi (ConsumerChoice)
Graphically, we can see differentindifference curves of a consumer
choosing between clothing and foodRemember that U3 > U2 > U1 for our
indifference curves
Consumer wants to choose highest utility
within their budget
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Tketici Tercihi (ConsumerChoice)
U3
D
C
Food(units per week)40 8020
Clothing(units per
week)
20
30
40
0
U1
A
B
A, B, C on budget lineD highest utility but notaffordableC highest affordableutilityConsumer chooses C
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Tketici Tercihi (ConsumerChoice)
Consumer will choose highestindifference curve on budget line
In previous graph, point C is where theindifference curve is just tangent to thebudget line
Slope of the budget line equals the slope
of the indifference curve at this point
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Tketici Tercihi (ConsumerChoice)
Recall, the slope of an indifference curveis:
F
CMRS(
(!
C
F
P
PSlope !
Further, the slope of the budget line is:
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Tketici Tercihi (ConsumerChoice)
Therefore, it can be said at consumersoptimal consumption point,
y
C
F
PPxMRS
P
PMRS
!
!
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Tketici Tercihi (ConsumerChoice)
It can be said that satisfaction ismaximized when marginal rate of
substitution (ofFandC) is equal to theratio of the prices (ofFandC)
Note this is ONLY true at the optimalconsumption point
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Tketici Tercihi (ConsumerChoice)
Optimal consumption point is wheremarginal benefits equal marginal costs
MB = MRS = benefit associated withconsumption of1 more unit of food
MC = cost of additional unit of food 1 unit food = unit clothing
PF/PC
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Tketici Tercihi (ConsumerChoice)
Food (units per week)
Clothing(units per
week)
40 8020
20
30
40
0
PointB does notmaximize satisfaction
because the
MRS = -10/10 = 1is greaterthan theprice ratio = 1/2
+10F U1
-10C
B
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ConsumerChoice:An Application Revisited
Consider two groups of consumers, eachwishing to spend $10,000 on the styling
and performance of a carEach group has different preferences
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ConsumerChoice:An Application Revisited
Styling
Performance$10,000
$10,000 These consumerswant performance
worth $7000 and styling
worth $3000
$3,000
$7,000
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ConsumerChoice:An Application Revisited
These consumerswant styling worth
$7000 and
performance worth$3000
$3,000
$7,000
Styling
$10,000
$10,000
Performance
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Gelirtketim erisi/Engel Erisi
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Gelirkame (Hicks Yaklam)
Figure 4-6: The Total Effect
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Figure 4-6: The Total Effectofa Price Increase
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