1. Words you need to know Market Demand/Supply Quantity Demanded/Supplied
Change In Quantity Demanded/Supplied
Change in Demand/Supply
Equilibrium Price(Market clearing price)
Surplus/Shortage

2. Markets Markets are where buyers and sellers trade
We will look at only pure competitive markets
These markets are the supply market and the demand market (resource and product)

3. Law Of Demand
Ceteris paribus, as P (Price) increases the quantity demanded of a product declines
So there is an inverse relationship between P (price) and the quantity demanded.
Consumers will buy more at lower prices than at higher prices.
This is the law of demand. MEMORIZE IT!
In this case ceteris paribus refers to anything that can affect demand or the quantity demanded except P

4. Explanations Why does the law of demand exist?
1. DMU-diminishing marginal utility
2. Income Effect
3. Substitution Effect
The curve slopes downward from the left to indicate the inverse relationship between P and QD. This means that as P and QD change we can only move along the demand curve that already exists. We cannot move the curve itself to the left or to the right.

5. Fuller Explanations
DMU-the decrease in added satisfaction as one consumes additional units of a product… less utility or satisfaction than the first
Income Effect: a lower price increases the power of money to purchase without increasing or decreasing actual income
Substitution Effect: a lower price gives incentive to substitute a lower priced good for a “now” relatively higher priced one

6. The “Other” things affecting Demand other than P
Things other than P (which causes changes in QD only) can cause changes in Demand itself. These changes will indicate a movement of the Demand Curve itself and not movement along an existing Demand curve. Yes, I’ll explain. This is probably the most difficult thing to understand because we casually misuse the term demand in conversation and by doing so misunderstand it intellectually as well.

7. 3. Changes in Income of consumers (normal goods and inferior goods)
Determinants of demand that will indicate changes in the position of the demand curve
1. Tastes of consumers
2. Number of consumers
3. Changes in Income of consumers (normal goods and inferior goods)
4. Prices of related goods
5. Expectations of consumers

8. Let’s Do some exercises
If the price of beef increases how will this affect the demand for beef?
If consumers lose income what will happen to the demand for new cars?
If there is an outbreak of plague what will happen to the demand for public transportation? For anti-plague vaccines?
If consumers find a new “fad” what could you expect to happen to demand for that product?
IF the price of Japanese cars increases for US consumers, what will happen to the demand for American make cars? To the demand for Japanese cars in the US?

9. Supply and its law The Law of Supply:
Producers will produce and sell more of their product at a high P than at a low P.
So, there is a direct relationship between price and QS (quantity supplied.)
The concept of the Law of supply is foreign to us. It will be hard for you to forego your consumer mentality when looking at supply. Just be aware of this.

10. Explanations Incentives with higher prices for producers
There are some constraints on production even at higher prices.
QS will only change with a change in P. A change in QS will be indicated ONLY by movement along an existing supply curve. Changes in the ceteris paribus conditions of non price determinants can and will result in a movement of the S curve itself. We have already run into this with Demand so you should be more familiar with it now.

11. 1. Changes in resources prices 2. Changes in technology
Determinants of Supply that will indicate changes in the position of the supply curve itself
1. Changes in resources prices
2. Changes in technology
3. Taxes and subsidies
4. Prices of related goods (if P of substitute gd increases)
5. Expectations
6. Number of sellers

12. Combining Supply and Demand or creating equilibrium
The point where demand curve and supply curve intersect is the equilibrium point in this particular market. That is where the EQP and EQQ are.
At prices above EQP there is a surplus
At prices below EQP there is a shortage
EQP is also called the market clearing price
There is also an EQQ or equilibrium quantity.
We do not say demand and supply are equal at the equilibrium point instead we simply call it the equilibrium price and quantity point.

13. Rationing function of price
In a free market the movements of price are essentially the governors of how much of a product can be produced and sold.
What this means is that price serves as a means of rationing goods and services.

14. Surpluses and Shortages