consumer behavior and demand chapter 3. characteristics of consumer behavior human wants are...
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Consumer Behavior and Demand
Chapter 3
Characteristics of Consumer Behavior
Human wants are insatiable More is preferred to less
Utility
Utility is defined as the amount of satisfaction received from a good or bundle of goods.
Cardinal measures of utility Numbers provide a measure of how much
more you like one good over another Ordinal measure of utility
Numbers provide a measure preference ranking
Cardinal versus Ordinal measures
Law of Diminishing Marginal Utility
As a person consumes additional units of a product, they derive less satisfaction from each additional unit.
Marginal Utility is equal to the additional utility derived from consuming one more unit of a good.
Utility from Pizza
Pizza Slices Total Utility Marginal Utility
1 2 3 4 5 6
5 9 12 14 15 15
Utility from Pizza
Pizza Slices Total Utility Marginal Utility
123456
59
12141515
5
Utility from Pizza
Pizza Slices Total Utility Marginal Utility
123456
59
12141515
54
Utility from Pizza
Pizza Slices Total Utility Marginal Utility
123456
59
12141515
543210
4x4 Trucks Total Utility Marginal Utility
1234
500850
10751175
500350225100
Utility from Trucks
Let’s throw in a John Deere tractor
4x4 Trucks Total Utility Marginal Utility
1234
One big greenmachine
500850
107511751175
500350225100
0
Now let’s try that Kubota
4x4 Trucks Total Utility Marginal Utility
1 2 3 4
One big orange machine
500 850
1075 1175
200,000,000
500 350 225 100
199,999,825
Wow, would you look at that!
Choices in Consumption Let’s move from one good to two now
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
. This dot represents a consumption bundle for the consumer
In math it is an ordered pair and can be calculated like this (# Cokes, # Pizzas)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
. This dot represents a consumption bundle for the consumer
In math it is an ordered pair and can be calculated like this (# Cokes, # Pizzas)
Therefore this bundle of goods is made upof one coke and seven pizza slices
(1,7)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
.
.. .
.Several Ordered Pairs = (# Cokes, # Pizzas)
These represent different consumption bundles for the consumer
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
.
.. .
.(1,7)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
.
.. .
.(1,7)
(2,5)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
.
.. .
.(1,7)
(2,5)
(10,1)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
.
.. .
.(1,7)
(2,5)
(10,1)
(6,2)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
.
.. .
.(1,7)
(2,5)
(10,1)
(6,2)
(3,3)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
.
.. .
.(1,7)
(2,5)
(10,1)
(6,2)
(3,3)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
This line is called an indifference curve
It can be labeled I or U for Utility Curve
I
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Every point on an indifference curve givesthe consumer the same level of utility or satisfaction
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Indifference curves are:Continuous
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Indifference curves are:Continuous
This one is not continuous
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Indifference curves are:ContinuousConvex to the origin
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Indifference curves are:ContinuousConvex to the origin
This is not convex to the origin
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Indifference curves are:ContinuousConvex to the originFill the plane and never cross
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Indifference curves are:ContinuousConvex to the originFill the plane and never cross
These cross and just make a mess.
Choices in Consumption
Why can’t they cross?
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
The farther the indifference curve is awayfrom the origin the better off the consumer is. The more of each good they have:-)
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Better Off
Worse Off
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Indifference curves are convex to the originthis gives us the Law of Diminishing Marginal Rate of Substitution
What is means is that we are willing to give up fewer and fewer slices of pizza to get an additional coke
Choices in Consumption
Choices in Consumption
Pizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Remember I said we are constrained, in otherwords we can’t get everything we want. How is that represented on this graph?
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Let’s say we have $10 to spend a day onpizza and coke, what does that constraint look like?
Well we need to know a couple other thingslike what are the prices of coke and pizza.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
If the price of pizza is $2 a slice how manycan we afford if we spend all our money income on pizza?
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
If the price of pizza is $2 a slice how manycan we afford if we spend all our money income on pizza? The answer is 5 slices..
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
If the price of coke is $1 a glass how manycan we afford if we spend all our money income on coke?
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
If the price of coke is $1 a glass how manycan we afford if we spend all our money income on coke? The answer is 10 cokes.
.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
These are the two endpoints of what is known as a budget constraint. You can afford to purchase one or the other.
.
.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
The budget constraint shows every possiblecombination of goods that the consumer can purchase with a certain money income.In this case it’s $10
.
.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
How do we answer the question of how consumers choose how much of each to consume? Remember what a utility curve represents?
.
.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Which point do you think the consumer willchoose A, B or C? Why did you choose thatpoint?
.
.A
B
C
..
. I1I2
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Which point do you think the consumer willchoose A, B or C? Why did you choose thatpoint?
.
.A
B
C
..
. I1I2
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
What happens to the budget constraintwhen the price of a good changes?
BC
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
If the Price of Coke doubles to $2.00 the budget constraint moves. More specifically it rotates clockwise with the Pizza slice endpoint staying the same.It rotates until the coke endpoint is on 5.
BC
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
This is because we can only afford 5cokes if when spend all of our income on coke now.
BC1BC2
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
What happens in a case where the pricesof both pizza and coke double?
BC
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
What happens in a case where the pricesof both pizza and coke double? The new budget constraint shifts inward with the endpoints 2.5 pizza slices and 5 cokes. Itis a parallel shift.
BC1BC2
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
How does our consumption change now?
BC1BC2
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
How does our consumption change now?
BC1BC2
A.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
How does our consumption change now? We move from point A to Point B.
BC1BC2
A
.B
.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets go back to the example where theprice of coke goes from $1 to $2. How doesthat affect consumption?
BC1
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets go back to the example where theprice of coke goes from $1 to $2. How doesthat affect consumption?
BC1BC2
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets go back to the example where theprice of coke goes from $1 to $2. How doesthat affect consumption?
BC1BC2
.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets go back to the example where theprice of coke goes from $1 to $2. How doesthat affect consumption?
BC1BC2
..
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets go back to the example where theprice of coke goes from $1 to $2. How doesthat affect consumption?
BC1BC2
.
Choices in Consumption
Substitution Effect - when the price of a good changesrelative to another good, we substitute consumption towardsthe good that has become relatively less expensive.
Income Effect - When the price of a good decreases the consumers real income has risen, thus creating the potentialfor consumption of both goods to increase.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets see how we can use this utility analysis to map out a demand curve for this consumer
BC1
.We start here with the price of coke at $1. When the price is $1 the consumerbuys 5 cokes and 2.5 slices of pizza.
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets have the price of coke increasingfrom $1 to $2. How does that affect consumption?
BC1BC2
..
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Coke consumption goes from 5 units down to 3 units. The price goes up, consumption goes down. (Follows theLaw of Demand)
BC1BC2
..
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets map out this consumer’s demandcurve.
BC1BC2
..
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1
Now lets map out this consumer’s demandcurve.
BC1BC2
..How many cokes will this consumer buyat a price of $1……. 5 Cokes
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
Choices in ConsumptionPizza Slices
Coke1 2 3 4 5 6 7 8 9 10 11 12
7
6
5
4
3
2
1BC1BC2
..How many cokes will this consumer buyat a price of $2……. 3 Cokes
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
. (3, $2.00)
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
. (3, $2.00)
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
. (3, $2.00)
Demand Curve for Coke
Choices in Consumption
Now we need to be able to determine the market demand curve for a product like this coke for an individual.
Choices in Consumption
Now we need to be able to determine the market demand curve for a product like this coke for an individual.
The market demand curve is the horizontal summation ofall individual demand curves for that particular good.
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
. (3, $2.00)
Jane’s Demand Curve for Coke
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
.(2, $1.50)
Bill’s Demand Curve for Coke
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
.(2, $1.50)
Bill’s Demand Curve for Coke
. (5, $1.00)
. (3, $2.00)
Jane’s Demand Curve for Coke
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
. (5, $1.00)
.(2, $1.50)
Bill’s Demand Curve for Coke
. (5, $1.00)
. (3, $2.00)
Jane’s Demand Curve for Coke
. (4, $1.50)
Choices in ConsumptionPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50
(6, $1.50)
(10, $1.00)
. (3, $2.00)
Market Demand Curve for Coke
..
Types of Demand
Types of Demand
Elastic Demand - When the quantity responseis relatively large compared to the price change.
Types of Demand
Elastic Demand - When the quantity responseis relatively large compared to the price change.
Price Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Elastic Demand
Types of Demand
Elastic Demand - When the quantity responseis relatively large compared to the price change.
Price Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Elastic Demand
If you lower price total revenue increases
Types of Demand
How is total revenue calculated?
Types of Demand
How is total revenue calculated?
It is the price of the product times the quantity sold
Types of DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Elastic Demand
.Total
Revenue =$8
When Price = $2
Types of DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Elastic Demand
.Total
Revenue =$12
When Price = $1
Types of Demand
Inelastic Demand - When the quantity responseis relatively small compared to the price change.
Types of Demand
Inelastic Demand - When the quantity responseis relatively small compared to the price change.
Price Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Inelastic Demand
Types of Demand
Inelastic Demand - When the quantity responseis relatively small compared to the price change.
Price Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Inelastic Demand
If you lower price total revenue decreases
Types of Demand
Remember total revenue is calculated by the price of the product times the quantity sold
Types of DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Inelastic Demand
Total Revenue
=$6
When Price = $3.
Types of DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Inelastic Demand
TotalRevenue =
$5
When Price = $1
.
Types of DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Inelastic Demand
TotalRevenue =
$5
When Price = $1
.
Types of Demand
Elasticity of Demand is considered to be Unitary when thePercentage changes in price and quantity demanded are the same.
In this case an increase in price doesn’t change the levelof income.
Types of Demand
How do you calculate the Elasticity of Demand?
Price Elasticity of Demand =
%Change in Quantity
% Change in Price
Types of Demand
How do you calculate the Elasticity of Demand?
Price Elasticity of Demand =
Q2 - Q1
P2 - P1
Q2 + Q1
P2 + P1
Price Elasticity of Demand
Ed > 1, Elastic Ed < 1, Inelastic Ed = 1, Unitary Elastic
One important note is that all of these elasticities are negative, So we just take the absolute value of them. The sign for a Price elasticity is meaningless.
Factors That Influence DemandElasticities
How many close substitutes there are for the product
Whether or not there are many alternative uses for the product
Whether the product is a major expenditure in the consumers budget
Factors That Influence DemandElasticities
What is the difference between a Change in Quantity Demanded and a Change in Demand?
A change in Quantity DemandedPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Demand for Coke
.
A change in Quantity DemandedPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Demand for Coke
.
. Price goes up from $1 to $3 and the Quantity Demanded goes down from5 cokes to 2.
A change in Quantity DemandedPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Demand for Coke
.
.Notice the demand curve did not change, However the consumer’s position on that Demand curve did change.
A change in Quantity DemandedPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Demand for Coke
.
.A change in Quantity Demanded impliesA movement along the demand curve.
A price increase implies that QuantityDemanded decreases.
A Change in DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Coke
.A change in Demand impliesA movement of the the demand curve.
A Change in DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Coke
.A change in Demand impliesA movement of the the demand curve.
New Demand for Coke
A Change in DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50 Demand for Coke
..A change in Demand impliesA movement of the the demand curve.
Now at $3 the consumer demands4.5 units instead of the initial 2.
New Demand for Coke
A Change in DemandPrice Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Coke
..A change in Demand impliesA movement of the the demand curve.
Now at $3 the consumer demands4.5 units instead of the initial 2.
Demand is said to have risenFor this product.
New Demand for Coke
What Creates Changes in Demand?
Population Income Tastes and Preferences Related Product Prices People’s Expectations
A Change in Demand from Population
Price Coke $
Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Coke
An increase in Population shifts the demand curve outward.
New Demand for Coke
A Change in Demand from Income
Price Steak $
Steak1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Steak
An increase in Income shifts the demand curve for Steak to the right
New Demand for Steak
A Change in Demand from Income
Price Spam $
Spam1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Spam
An increase in Income shifts the demand curve for Spam or Riceto the left
New Demand for Spam
A Change in Demand from a Change in Tastes and Preferences
Price HealthFood $
Q Health Food1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Health Food
An increase in Health Concerns shifts the demand curve for Health Food to the right
New Demand for Health Food
A Change in Demand from a Change in the price of a Related Good
Price Coke $
Q Coke1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Coke
An increase in the price of Pepsi shifts the demand curve for Coke to the right
New Demand for Coke
They are Substitutes
A Change in Demand from a Change in the price of a Related Good
Price Hamburgers $
Q Hamburgers1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Hamburgers
An increase in the price of French Fries shifts the demand curve for Hamburgersto the left
New Demand for Hamburgers
They are Complements
A Change in Demand from a Change in Consumer’s Expectations
Price Gasoline $
Q Gasoline1 2 3 4 5 6 7 8 9 10 11 12
3.50
3.00
2.50
2.00
1.50
1.00
.50Demand for Gasoline
If consumers expect there to be a shortageOn gasoline, then the demand curve forGasoline will shift to the right.
New Demand for Gasoline
Income Elasticities
Income Elasticity =
% Change in Quantity of Product
% Change in Income of Consumer
Income Elasticities
Engel Curve – The relationship between the consumers income and the quantity he or she purchases of an item.
Engel Curve for Food
Quantity Food Purchased
Weekly Income in 000’s
1 2 3 4 5 6 7 8 9 10 11 12
Engel Curve for Clothing
Quantity ClothingPurchased
Weekly Income in 000’s
1 2 3 4 5 6 7 8 9 10 11 12
Income Elasticities
Income Elasticity =
Q2 - Q1
I2 - I1
Q2 + Q1
I2 + I1
Income Elasticities
Ei > 0, Normal Good Ei < 0, Inferior Good
Ei> 1, Luxury Ei< 1, Necessity
Cross Price Elasticities
Cross Price Elasticities measure the responsivenessOf Demand for good 1 to a change in the price of good 2
Answers the question: How does the quantity demanded of coke Change from a change in the price of pepsi?
Cross Price Elasticities
For Substitutes: An increase in the price of one Will increase the demand of the other.
The Cross Elasticity of Coke for Pepsi is > 0
Ec,p>0
Coke and Pepsi
Cross Price Elasticities
For Complements: An increase in the price of one will decrease the demand of the other.
The Cross Elasticity of Hamburgers for French Fries is < 0
Eh,ff <0
Hamburgers and French Fries