affect total revenue and total expenditure depending on the price elasticity of demand for the good.. Explain the cross-price elasticity of demand and.[r]
(1)41
Elasticity
Chapter 4
(2)(3)43
1 Define price elasticity of demand and explain what
determines whether demand is elastic or inelastic
2 Calculate the price elasticity of demand using
information from the demand curve
3 Understand how changes in the price of a good
affect total revenue and total expenditure depending on the price elasticity of demand for the good
4 Explain the cross-price elasticity of demand and
income elasticity of demand
5 Discuss the price elasticity of supply, explain what
determines whether supply is elastic or inelastic, and calculate the price elasticity of supply using
(4)Drug Enforcement and Local
Theft
•
Hypothesis
– Drug users steal to buy drugs
– Increasing drug enforcement will decrease theft
•
Analysis
– Increased enforcement reduces supply of drugs
• Price of drugs increases
• Quantity demanded decreases
– Theft goes down ONLY IF total expenditure on
drugs decreases
(5)45
Price Elasticity of Demand
•
Price elasticity of demand
is defined as the
percentage change in quantity demanded from a
1% change in price
– Measure of responsiveness of quantity demanded
to changes in price
•
Example:
– Price of beef decreases 1%
– Quantity of beef demanded
increases 2%
– Price elasticity of demand is –
P
(6)Calculate Price Elasticity
•
Symbol for elasticity is
ε
– Lower case Greek letter epsilon
•
For small percentage changes in price
ε = Percentage change in quantity demanded
Percentage change in price § Price elasticity of demand is always negative
(7)47
•
If price elasticity is greater than 1, demand is
elastic
– Percentage change in quantity is greater than
percentage change in price
– Demand is responsive to price
3 Price Elasticity of Demand
Inelastic
Unit elastic
Elastic
2
(8)Inelastic Demand
•
If price elasticity is less than 1, demand is
inelastic
– Percentage change in quantity is less than
percentage change in price
– Quantity demanded is not very responsive to price
3 Price Elasticity of Demand
Inelastic
Unit elastic
Elastic
2
(9)49
Unit Elastic Demand
•
If price elasticity is 1, demand is
unit elastic
– Price and quantity change by the same percentage
3 Price Elasticity of Demand
Inelastic
Unit elastic
Elastic
2
(10)Example: Demand for Pizza
Old
New
% Change
Price
$1.00
$0.97
3%
Quantity
400
404
1%
ε = Percentage change in quantity demanded
Percentage change in price
ε = 1%