isolate the relationship of interest. We use the same method to make a graph.

Figure A1.8

(a) shows an example. This graph shows what happens to the quantity of ice cream consumed when the price of ice cream varies w• hile the temperature remains constant. The curve labeled 90°F shows the relationship between ice cream consumption and the price of ice cream if the temperature is 90°F. The numbers used to plot that curve are those i• n the first and fifth columns of the table in Figure A1.8 . For exa• ple, if the temperature is 90°F, 10 gallons of ice cream are consumed when the price is $3.25 a scoop.

We can also show the relationship between ice cream consumption and temperature while the price of ice cream remains constant, as shown in