ECON Notes Flashcards
How individuals
(consumers & firms) make choices (i.e.,
how do people make optimal decisions)
Optimization
How markets and
nonmarket institutions produce
outcomes in individuals’ decisions (i.e.,
what are the outcomes we observe
when individuals are making those
optimal decisions)
Equilibrium
Assumptions
Individual are _____________ & ___________
rational and act purposefully
Individuals maximize a measure of _______-______
Subject to some sort of _________ due to _______ resources
well-being (happiness, profit)
constraint, scare (budgets)
max (B(x) - C(x))
x is an activity level
B is the benefits received from that activity level
C is the costs you incur from the activity at level x
What is the law of demand
As price increase which is on the y axis quantity demanded decreases which explain the downward slope of the demand curve
Four key determinants of demand
- Preferences
- Price and availability of related
goods - Income
- Number of consumers (for market
demand)
Draw the demand curve for Q = 4-2P
P = 2 - 0.5Q
At a price of 0 the quantity demand is 4
When the quantity demanded is 0 the price is 2
Measures the sensitivity to changes in the environment
Elasticity
What is demand elasticity?
What is the formula?
When is it elastic, unit elastic, and inelastic
How much will quantity demanded change when price changes by x%?
Formula: %ΔQ/%ΔP
Elastic: -1:-infinity
Unity Elastic: -1
Inelastic: -1:0
What is the law of supply?
As the price increases the quantity supplied increases as well which explains the upward sloping supply curve
Determinants of Supply
Input prices (raw materials, labor)
➢ Technology (quality and availability)
➢ Alternative product lines
➢ # of firms in the market(more firm = more supply)
➢ Price and supply of joint products (ex:
as the demand/price of beef falls,
supply of leather falls)
➢ Time frame(firms can increase supply more in the long run than the short run)
Draw a supply curve for Q=2P-20
What happens if price is 20?
P=10+0.5Q
What is Supply elasticity
What is the formula?
What is inelastic, unit elastic, and elastic
Measures a firms’ sensitivity to price changes
Formula: %ΔQ/%ΔP
Inelastic: 0:1
Unit Elastic: 1
Elastic: 1:infinity
_________ is one of the most important factors influencing supply elasticity
Why?
Time
In the long run firms can change supply more than in the short run
What are the four main assumptions for competitive markets?
- Many consumers & firms on both sides of the
market
a. “Price Takers”: No one has the power to
unilaterally set prices - Common knowledge
a. The market has a free flow of information - No collusion
a. Firms cannot explicitly cooperate to
affect prices and quantities in the market - Free entry & exit
a. Firms enter and leave the market as they
find it profitable to do so
b. Lack of technical/leg
What is market equilibrium
Where the supply and demand curve intersect
Example for market equilibrium
QD = 260-20P
Qs=32P-104
P=8
P=6
P=7
P=13-0.05QD
P=3.25 + 0.03125QS
P=7 equilibrium
How to find competitive equilibrium
I. P = 20 – 2QD
II. QS = P – 5
Set the equations equal to each other when both equation are at QD=QD and P=P
Solution
In equilibrium, QS = QD
➢ P – 5 = 10 – 0.5P
3. Solve for P
➢ 1.5P = 15
➢ P = 10
4. Substitute P into either the demand or supply curve to find Q
1. QD = 10 – 0.5(10) = 5
2. QS = 10 – 5 = 5
Benefit from
obtaining a product at a price less
than the maximum willingness to pay
Consumer surplus
Benefit from selling
at a price greater than minimum
required
Producer Surplus
Calculate Consumer surplus
Demand: QD = 260 – 20P
Supply: QS = 32P - 104
Equilibrium: P = 7, Q = 120
Consumer Surplus = 360
Producer Surplus = 225
Consumers willing to pay more than it
costs society to produce
A “_________ __________” occurs when resources are not efficiently allocated in the market
An example of what can cause this is in markets owned by a
__________
deadweight loss
monopolist
Let’s suppose a monopolist with a
cost per unit of $2 faces a demand
curve of P = 10 – Q
Supply curve is flat @ $2
Instead of selling 8 units @ 2 ($16 total
revenue), they can raise the price to $6
and sell 4 units ($24 total revenue) –
but you can see there is lost value to
the market because there were less
units sold
Not sure on how to do this yet
What is the income effect
As income grows, we demand more
What is the substitution effect
As prices increase and income stays the same, demand decreases
How to find the total demand curve for a market
Example
Jose’s preferences for Coca Cola yield this demand curve: QJ = 4 – 2P
Kayla’s preferences yield this demand curve: QK = 3 – P
➢ Total Market Demand: Q = 7 - 3P
What are ways to learn about the demand in a market for a firm and what is the best way?
Marketing surveys
Ask people what they’d pay!
However, what people say and do can be different
Price experimentation(best way)
Test effects of small changes in the market
Econometric studies
Very tricky to do properly
What causes a change in demand (3 things)
Response to change in price
Response to related Goods
Substitutes ( A & B are substitutes A increases, buy more of B)
Complements (C & D are complements, C increases, buy less of D)
Response to Income
Normal Goods
Inferior Goods
Luxury Goods
_________ changes along the demand curve
elasticity