微观经济学原理曼昆英文第七章PPT课件

name WTP
Anthony $250
Chad
175
Flea
300
John
125
A: Anthony & Flea will buy an iPod, Chad & John will not.
Hence, Qd = 2 when P = $200.
4
WTP and the Demand Curve
▪ First, we look at the well-being of consumers.
2
Willingness to Pay (WTP)
A buyer’s willingness to pay for a good is the maximum amount the buyer will pay for that good.
▪ how much of each good is produced ▪ which producers produce it ▪ which consumers consume it
▪ Welfare economics studies how the allocation
of resources affects economic well-being.
01234
7
WTP and the Demand Curve
P
$350 $300 $250 $200 $150 $100
$50
Flea’s WTP Anthony’s WTP
Chad’s WTP John’s WTP
At any Q, the height of the D curve is the WTP of the marginal buyer, the buyer who would leave the market if P were any higher.
supply curve?
▪ Do markets produce a desirable allocation of
resources? Or could the market outcome be improved upon?
1
Welfare Economics
▪ Recall, the allocation of resources refers to:
$0
Q
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Consumer Surplus (CS)
Consumer surplus is the amount a buyer is willing to pay minus the amount the buyer actually pays:
CS = WTP – P
name WTP
Anthony $250
Chad
175
Flea
300
John
125
Suppose P = $260.
Flea’s CS = $300 – 260 = $40.
The others get no CS because they do not buy an iPod at this price.
Total CS = $40.
Biblioteka Baidu
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WTP measures how much the buyer values the good.
name WTP
Anthony $250
Chad
175
Flea
300
John
125
Example: 4 buyers’ WTP for an iPod
3
WTP and the Demand Curve
Q: If price of iPod is $200, who will buy an iPod, and what is quantity demanded?
If there were a huge # of buyers, as in a competitive market,
there would be a huge # of very tiny steps,
and it would look more like a smooth curve.
$0
Q
126 – 175
Chad, Anthony, Flea
3
125
0 – 125
John, Chad, Anthony, Flea
4
5
WTP and the Demand Curve
P
$350 $300 $250
P $301 & up
$200
251 – 300
$150 $100
$50 $0
176 – 250 126 – 175
0 – 125
Q
01234
Qd 0 1 2 3 4
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About the Staircase Shape…
P
$350 $300 $250 $200 $150 $100
$50
This D curve looks like a staircase with 4 steps – one per buyer.
7 C H A P T E R
Consumers, Producers, and the Efficiency of Markets
Economics P R I N C I P L E S O F
N. Gregory Mankiw
© 2009 South-Western, a part of Cengage Learning, all rights reserved
Derive the demand schedule:
P (price of iPod)
who buys
Qd
$301 & up nobody
0
name WTP 251 – 300 Flea
1
Anthony $250 176 – 250 Anthony, Flea
2
Chad Flea John
175 300
CS and the Demand Curve
P
$350 $300 $250 $200
Flea’s WTP
P = $260
In this chapter, look for the answers to these questions:
▪ What is consumer surplus? How is it related to the
demand curve?
▪ What is producer surplus? How is it related to the