Economics, 3rd Edition

Variables That Influence Buyers

This table lists the variables that affect how much consumers choose to buy of any good. Notice the special role that the price of 

the good plays: a change in the good’s price represents a movement along the demand curve, whereas a change in one of the other 

variables shifts the demand curve.

TABLE 3.1

Variable

A change in this variable . . .

Price

Is represented as a movement along 

the demand curve

Prices of other, related goods

Income

Shifts the demand curve

Shifts the demand curve

Tastes

Shifts the demand curve

Population

Shifts the demand curve

Advertising

Shifts the demand curve

Expectations

Shifts the demand curve

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CHAPTER 3  THE MARKET FORCES OF SUPPLY AND DEMAND  49

SELF TEST 

Make up an example of a demand schedule for pizza and graph the demand curve. Give an 

example of something that would cause the demand curve to shift to the right. Give a different example of 

something that would cause the demand curve to shift to the left.