Macroeconomics 11th Edition by Michael Parkin

Exercise 37

Explain how we "read" the three graphs in Fig. l and 2.
FIGURE 1 Making a Graph

Graphs have axes that measure quantities as distances. Here, the horizontal axis ( x -axis) measures temperature, and the vertical axis ( y -axis) measures height. Point A represents a fishing boat at sea level (0 on the y -axis) on a day when the temperature is 32°F. Point B represents a climber at the top of Mt. McKinley, 20,320 feet above sea level at a temperature of 0°F. Point C represents a climber at the top of Mt. McKinley, 20,320 feet above sea level at a temperature of 32°F.
FIGURE 2 Two Graphs of Economic Data

The graph in part (a) tells us that in 2010, 3.8 million songs per day were downloaded at an average price of $1.37 per song.
The graph in part (b) tells us that in 2010, 3.8 million songs per day and 0.2 million albums per day were downloaded.