micro 2.5/ 2.6- elasticities of demand/supply Flashcards
Define elasticity
elasticity shows how sensitive/responsive one variable is to another
Define PED, or Price Elasticity of Demand.
PED measures the responsiveness of Qd (quantity demanded) due to changes in price.
Describe the diagram for a highly responsive or elastic good.
The slope/gradient will be flatter
Describe the diagram for a less responsive or inelastic good.
The slope/gradient will be steeper
State the formula for PED
PED= percentage change in Qd/percentage change in price
PED will always have a ——– value due to the ——–.
PED will always have a negative value due to the law of demand.
What is the rule for categorising PED?
Use the absolute value of the PED, ignoring the minus sign.
State the 5 ranges of PED
- inelastic
- elastic
- perfectly inelastic
- perfectly elastic
- unitary elastic
Describe an inelastic PED
- when (the Qd of) something is not very responsive (to changes in price).
- 0<|PED|<1
- %∆P>%∆Qd
- gradient of demand curve steeper
Describe an elastic PED
- when (the Qd of) something is very responsive (to changes in price).
- |PED|>1
- %∆P<%∆Qd
- gradient of demand curve flatter
Describe a perfectly inelastic PED
- vertical demand curve
- PED=0
- Qd does not respond to changes in P
Give an example of where a perfectly inelastic PED may occur
An essential medicine with no substitutes.
Describe a perfectly elastic PED
- horizontal demand curve
- PED= ∞
- Qd is entirely dependent on P (buyers will only buy at one price and no other)
Give an example of where a perfectly elastic PED may occur
very theoretical, but luxury products like high end cars
Describe a unitary elastic PED
- hyperbola demand curve
- |PED|=1
- %ΔP=%ΔQd
effect of a PED determinant on a demand graph
affects the slope of the curve
state the 4 PED determinants
- number and closeness of substitutes
- Degree of necessity
- proportion of income spent on good
- time
(never deprive people of time)
Describe number and closeness of substitutes as a PED determinant
- many and close substitutes= elastic (consumer can switch to other substitutes easily)
- few/remote substitutes= inelastic (consumers do not have as many options)
Describe degree of necessity as a PED determinant and give examples
- necessity= inelastic (eg medicine, food, water)
- luxury= elastic (eg holidays abroad, high end cars)
Describe proportion of income spent on a good as a PED determinant
- small proportion (cheap)= inelastic as disposable income Yd is not affected significantly
- large proportion (expensive)= elastic as disposable income Yd is affected significantly