Economics, 3rd Edition

56  PART 2  SUPPLY AND DEMAND: HOW MARKETS WORK

SELF TEST 

Using the supply equation:

Qs

= 2 + 3p

Calculate quantity supplied if p

= 40

Calculate price if Qs

= 88 

Variables That Influence Sellers

This table lists the variables that affect how much producers choose to sell 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 supply curve, whereas a change in one of the other variables shifts the 

supply curve.

TABLE 3.2

Variable

A change in this variable . . .

Price

Is represented by a movement along the  

supply curve

Profitability of goods in production and  

price of goods in joint supply

Shifts the supply curve

Technology

Shifts the supply curve

Natural/social factors

Shifts the supply curve

Input costs

Shifts the supply curve

Expectations of producers

Shifts the supply curve

Number of sellers

Shifts the supply curve