Law of Demand
if price goes up, quantity demanded goes down and vice versa
Substitution effect
if price goes up for a product, consumers buy less of that and more of another product
Income effect
if price goes down, consumer’s purchasing power increases so they buy more
Market demand
sum of all individual quantities demanded
Substitutes
goods can replace each other price. price of one increases, demand for other increases
Complements
goods are bought and used together. price of one increases, demand for other decreases
Normal goods
income increases, so does demand
Inferior goods
income increases, demand decreases
Law of supply
direct relationship between price and quantity supplied (positive slope)
Consumer surplus
difference between what you are willing to pay (buyer max - price) and actually pay OR difference between total benefit and cost
Producer surplus
difference between price seller received (price - seller min) and how much they will sell for
Total surplus
consumer + producer surplus
Total producer/consumer surplus
area of the whole triangle
PES
% change in Q/% change in P
Inelastic < 1 < elastic
PED
|% change in Q/% change in P| (inside always negative)
Inelastic < 1 < elastic
XED
% change in Q of product A/$ change in P of product B
Positive: substitute, Negative: complement
YED
% change in Q/% change in Income
Positive: normal good, Negative: inferior good
% change in P
(New P - Old P)/Old P *100
Total Revenue test
Price * Quantity
Inelastic: price and TR are direct, Elastic: Price and TR are inverse