2. bÖlÜm

2. BÖLÜM

TÜKETİCİ TERCİHLERİ(Consumer Preferences)

AmaçlarımızTüketici tercihini açıklamakFayda Kavramanı açıklamakFiyat ve gelirin önemiOptimal davranışTüketici dengesi

Anahtar kavramlar: Homo-economicus, fayda fonksiyonu, farksızlık eğrileri, marjinal ikame oranı, bütçe Kısıtı, tüketici dengesi, gelir ikame etkisi, bireysel talep fonksiyonu

İhtiyaç ve Tüketici Tercihleri /Kavramlar

İhtitaç: Karşılandığında insanlara haz, karşılanmadığında ise elem, ve doyumsuzluk veren duygudur (açlık ve susuzluk gibi)

Mal: İnsan ihtiyaçlarını karşılayan her türlü fiziki varlık ve hizmetlerdir.

Tüketici: Mal tüketerek ihtiyaçlarını karşılayan kimsedir.

Fayda: Malların ihtiyaçları giderme özelliğidir.

İktisadi Akılcılık ve Homo-Economicus

1. Tam bilgiye sahip olma,2. Seçici olma,3. Çoğu aza tercih etme,4. Tercihler arasında tutarlı olma.

Fayda Kavramı

Malların ihtiyaçlarını giderme özelliğidir.Kardinal ve ordinal yaklaşım

Fayda ölçülebilir [Jevons (1854) ve Walras (1874)]

Fayda ölçülemez [Edgeworth (1881), Antonelli (1886), İrving Fisher (1892)]

Değer paradoksu?

Fayda Kavramı/TU and MU

Fayda Fonksiyonu

There are three steps involved in the study of consumer behavior

1. Consumer Preferences To describe how and why people prefer

one good to another

2. Budget Constraints People have limited incomes

Farksızlık Eğrileri (Indifference Curves:An Example)

Market Basket Units of Food Units of Clothing

A 20 30

B 10 50

D 40 20

E 30 40

G 10 20

H 10 40

The consumer prefersA to all combinations

in the yellow box, whileall those in the pink

box are preferred to A.


Food

10

20

30

40

10 20 30 40

Clothing

50

G

A

EH

B

D

•Indifferent between points B, A, & D•E is preferred to points on U1

•Points on U1 are preferred to H & G


Food

10

20

30

40

10 20 30 40

Clothing

50

U1

GD

A

EH

B

Farksızlık Eğrileri(Indifference Curves)

Farksızlık eğrisi üzerindeki her nokta, eşit toplam fayda

Mal düzleminin her noktasında farksızlık eğrisi geçer

Farksızlık eğrisi negatiftir Orjine dışbükeydir

U2

U3


Food

Clothing

U1

ABD

Market basket Ais preferred to B.Market basket B ispreferred to D.


Food

Clothing •B is preferred to D•A is indifferent to B & D•B must be indifferent to D but that can’t be if B is preferred to D

U1

U1

U2

U2

A

B

D

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

Marjinal İkame Oranı (Marginal Rate of Substitution)

Food

Clothing

2 3 4 512

4

6

8

10

12

14

16


Food2 3 4 51

Clothing

2

4

6

8

10

12

14

16 A

B

D

EG

-6

1

1

11

-4

-2-1

MRS = 6

MRS = 2

FCMRS

Azalan Marjinal İkame Oranı (Marginal Rate of Substitution)

MRS, kayıtsızlık eğrisi aşağı gittikçe azalır Along an indifference curve there is a

diminishing marginal rate of substitution (Azalan marjinal İkame eğrisi)

The MRS went from 6 to 4 to 1

Marjinal Fayda ve Tüketici Tercihi Marginal Utility and Consumer Choice

Formally:

C)( MUF) (MU CF 0

No change in total utility along an indifference curve. Trade off of one good to the other leaves the consumer just as well off.

Marginal Utility and Consumer Choice

Rearranging:

CF

CF

/MU MUMRS saycan We

C for F of MRSFCSince

MUMUFC

/

//


When consumers maximize satisfaction:

CF /P PMRS

CF CF /P P /MUMU

Since the MRS is also equal to the ratio of the marginal utility of consuming F and C


Rearranging, gives the equation for utility maximization:

CCFF PMUPMU //


Two polar cases are of interest Perfect substitutes (MRS sabit) Perfect complements (MRS=0)

Tüketici Tercihi/Kayıtsızlık Eğrisi

Orange Juice(glasses)

Apple Juice

(glasses)

2 3 41

1

2

3

4

0

Mükemmel İkame

(PerfectSubstitute

s)

Tüketici Tercihi/Kayıtsızlık Eğrisi

Right Shoes

LeftShoes

2 3 41

1

2

3

4

0

Mükemmel Tamamlayıcı(Perfect

Complements)

Tüketici Tercihi( Consumer Preferences)

These consumers

place a greater value

on performance than styling

Styling

Performance

Tüketici Tercihi( Consumer Preferences

These consumers place a greater value on styling

than performance

Styling

Performance

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 of

14 = 8 + 2(3)

Utility - Example

Market Basket

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 and prefers both to C

Utility - Example

Baskets for each level of utility can be plotted to get an indifference curve To find the indifference curve for a utility of

14, we can change the combinations of food and clothing that give us a utility of 14

Utility - Example

Food10 155

5

10

15

0

Clothing

U1 = 25U2 = 50

U3 = 100A

B

C

Basket U = FC C 25 = 2.5(10) A 25 = 5(5) B 25 = 10(2.5)

ICPFP CF

Bütçe Doğrusu (The Budget Line)

The budget line then can be written:

All income is allocated to food (F) and/or clothing (C)


Different choices of food and clothing can be calculated that use all income These choices can be graphed as the budget

lineExample:

Assume income of $80/week, PF = $1 and PC = $2

Bütçe Kısıtı(Budget Constraints)

Market Basket

FoodPF = $1

ClothingPC = $2

IncomeI = PFF + PCC

A 0 40 $80

B 20 30 $80

D 40 20 $80

E 60 10 $80

G 80 0 $80

C

F

PP

FC Slope -

21-


10

20

A

B

D

E

G

(I/PC) = 40

Food40 60 80 = (I/PF)20

10

20

30

0

Clothing


YXPP

PM

YPXPMYPXPM

Y

X

Y

YX

YX

Bütçe Doğrusu Değişimi(The Budget Line – Changes)

An increase inincome shifts

the budget lineoutward

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

Fiyat Değişiminin Etkisi (The Effects of Changes in Prices)

The Effects of Changes in Prices If the price of one good decreases, the

budget line shifts outward, pivoting from the other good’s intercept.

If the price of food decreases and you buy only food (x-intercept), then you can buy more food. The x-intercept shifts out.

If you buy only clothing (y-intercept), you can buy the same amount. No change in y-intercept.

Fiyat Değişiminin Etkisi (The Effects of Changes in Prices)

(PF = 1)L1

An increase in theprice of food to$2.00 changes

the slope of thebudget line and

rotates 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

Fiyat Değişiminin Etkisi /Talep fonk

Tüketici Tercihi (Consumer Choice)

Given preferences and budget constraints, how do consumers choose what to buy?

Consumers choose a combination of goods that will maximize their satisfaction, given the limited budget available to them


The maximizing market basket must satisfy 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 most preferred combination of goods and services


Graphically, we can see different indifference curves of a consumer choosing between clothing and food

Remember that U3 > U2 > U1 for our indifference curves

Consumer wants to choose highest utility within their budget


U3

D

U2

C

Food (units per week)40 8020

Clothing(units per

week)

20

30

40

0

U1

A

B

•A, B, C on budget line•D highest utility but not affordable•C highest affordable utility•Consumer chooses C


Consumer will choose highest indifference curve on budget line

In previous graph, point C is where the indifference curve is just tangent to the budget line

Slope of the budget line equals the slope of the indifference curve at this point


Recall, the slope of an indifference curve is:

FCMRS

C

F

PPSlope

Further, the slope of the budget line is:


Therefore, it can be said at consumer’s optimal consumption point,

y

C

F

PPxMRS

PPMRS


It can be said that satisfaction is maximized when marginal rate of substitution (of F and C) is equal to the ratio of the prices (of F and C)

Note this is ONLY true at the optimal consumption point


Optimal consumption point is where marginal benefits equal marginal costs

MB = MRS = benefit associated with consumption of 1 more unit of food

MC = cost of additional unit of food 1 unit food = ½ unit clothing PF/PC


If MRS ≠ PF/PC then individuals can reallocate basket to increase utility

If MRS > PF/PC

Will increase food and decrease clothing until MRS = PF/PC

If MRS < PF/PC

Will increase clothing and decrease food until MRS = PF/PC


Food (units per week)

Clothing(units per

week)

40 8020

20

30

40

0

Point B does not maximize satisfaction

because theMRS = -10/10 = 1

is greater than the price ratio = 1/2

+10F U1

-10C

B

Consumer Choice: An Application Revisited

Consider two groups of consumers, each wishing to spend $10,000 on the styling and performance of a car

Each group has different preferences


Styling

Performance$10,000

$10,000 These consumerswant performance worth $7000 and

styling worth $3000

$3,000

$7,000


These consumers want

styling worth $7000 and

performance worth $3000

$3,000

$7,000

Styling

$10,000

$10,000

Performance

Gelir tüketim eğrisi/Engel Eğrisi

Gelir İkame (Hicks Yaklaşımı)

Figure 4-6: The Total Effectof a Price Increase

Figure 4-7: The Substitution and Income Effects of a Price Change

2. bÖlÜm

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