Unit 2: Supply, Demand, and Consumer Choice

Demand Review What are the two key aspects of the definition of demand? What is the Law of Demand? Give an example of the substitution effect Give an example of the income effect Give an example of the law of diminishing marginal utility Explain how the law of diminishing marginal utility causes the law of demand How do you determine the MARKET demand for a particular good? Name 10 fast food places

This is a change in demand, not a change in quantity demanded Shifts in Demand CHANGES IN DEMAND Ceteris paribus-“all other things held constant.” When the ceteris paribus assumption is dropped, movement no longer occurs along the demand curve. Rather, the entire demand curve shifts. A shift means that at the same prices, more people are willing and able to purchase that good. This is a change in demand, not a change in quantity demanded Changes in price DON’T shift the curve!

What if cereal makes you smarter? Change in Demand What if cereal makes you smarter? Demand Schedule Price of Cereal $5 4 3 2 1 Price Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 4

Change in Demand Demand Schedule Price of Cereal $5 10 $4 20 $3 30 $2 Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 5

Change in Demand Demand Schedule Price of Cereal $5 10 $4 20 $3 30 $2 Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 6

Change in Demand Demand Schedule Price of Cereal $5 30 $4 40 $3 50 $2 1 Price Quantity Demanded $5 30 $4 40 $3 50 $2 70 $1 80 100 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 7

Prices didn’t change but people want MORE cereal Change in Demand Demand Schedule Price of Cereal Increase in Demand Prices didn’t change but people want MORE cereal $5 4 3 2 1 Price Quantity Demanded $5 30 $4 40 $3 50 $2 70 $1 80 100 D1 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 8

What if cereal causes baldness? Change in Demand Demand Schedule What if cereal causes baldness? Price of Cereal $5 4 3 2 1 Price Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 9

Change in Demand Demand Schedule Price of Cereal $5 10 $4 20 $3 30 $2 Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 10

Change in Demand Demand Schedule Price of Cereal $5 10 $4 20 $3 30 $2 Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 11

Change in Demand Demand Schedule Price of Cereal $5 10 $4 20 $3 30 $2 Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 12

Change in Demand Demand Schedule Price of Cereal $5 10 $4 20 $3 30 $2 Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 13

Prices didn’t change but people want LESS cereal Change in Demand Demand Schedule Price of Cereal $5 4 3 2 1 Decrease in Demand Prices didn’t change but people want LESS cereal Price Quantity Demanded $5 $4 5 $3 20 $2 30 $1 80 60 D2 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 14

What if the price of MILK goes up? Change in Demand Demand Schedule What if the price of MILK goes up? Price of Cereal $5 4 3 2 1 Price Quantity Demanded $5 10 $4 20 $3 30 $2 50 $1 80 Demand o 10 20 30 40 50 60 70 80 Q Quantity of Cereal 15

What Causes a Shift in Demand? 5 Shifters (Determinates) of Demand: Tastes and Preferences Number of Consumers Price of Related Goods Income Future Expectations Changes in PRICE don’t shift the curve. It only causes movement along the curve.

Tastes and Preferences Good examples here are fads in fashion or diet. When an item is popular or we have a preference for it, DEMAND increases. Examples: Silly-bands, Beats-by-Dre When the item loses popularity, DEMAND decrease.

Number of Consumers Demand for a product is based upon the number of potential consumers. On game day afternoons in Athens the DEMAND for food and beverages increases. By the next morning, DEMAND has decreased with the departure of fans.

Prices of Related Goods The demand curve for one good can be affected by a change in the price of ANOTHER related good. Substitutes are goods used in place of one another. If the price of one increases, the demand for the other will increase (or vice versa) Ex: If price of Oreos falls, demand for the genaric brand will… 2. Complements are two goods that are bought and used together. If the price of one increase, the demand for the other will fall. (or vice versa) Ex: If price of skis falls, demand for ski boots will...

Substitutes 20 20

Substitutes 21 21

Substitutes 22 22

Substitutes 23 23

Substitutes 24 24

Substitutes 25 25

Substitutes 26 26

Complements 27 27

Income The incomes of consumer change the demand, but how depends on the type of good. Normal Goods As income increases, demand increases As income falls, demand falls Ex: Luxury cars, Sea Food, jewelry, homes 2. Inferior Goods As income increases, demand falls As income falls, demand increases Ex: Top Ramen, used cars, used clothes, Spam-Inferior Yachts- Normal Off Brand Cereal-Inferior McDonald’s-Inferior Toilet Paper- Probably no connection to income (The point-some products are very reliant on income and others are not)

Inferior Goods 29 29

Future Price Expectations When you hear that the latest I-Phone will be sold at half-price during the month of December your DEMAND for it now _________________. However, if you hear that the price of the I-Phone will double for the Christmas shopping season, your DEMAND for it now ________________. Decreases Increases

Change in Qd vs. Change in Demand There are two ways to increase quantity from 10 to 20 Price of Cereal P A to B is a change in quantity demand (due to a change in price) A to C is a change in demand (shift in the curve) A C $3 $2 B D2 D1 o Q Cereal 10 20 Quantity of Cereal

Practice First, identify the determinant (shifter) then decide if demand will increase or decrease Shifter Increase or Decrease Left or Right 1 2 3 4 5 6 7 8 Number of consumers, increase. Income, decrease. Substitutes, decrease. Price doesn’t shift curve, no change. Tastes and preferences, decrease. Expectations, increase. Complements, decrease.

Hamburgers (a normal good) Practice First identify the determinant (Shifter). Then decide if demand will increase or decrease Hamburgers (a normal good) Population boom Incomes fall due to recession Price for Chicken Sandwiches falls to $1 Price increases to $5 for hamburgers New health craze- “No ground beef” Hamburger restaurants announce that they will significantly increase prices NEXT month Government heavily taxes shake and fries causes their prices to quadruple. Restaurants lower price of burgers to $.50 Number of consumers, increase. Income, decrease. Substitutes, decrease. Price doesn’t shift curve, no change. Tastes and preferences, decrease. Expectations, increase. Complements, decrease. 33 33