On a line graph that tracks a quantity over time, what does the y-axis represent?

On a line graph that tracks a quantity over time, what does the y-axis represent?

• A. The independent variable
• B. The dependent variable
• C. The rate of change
• D. A constant

Answer: (B)

The y-axis shows the quantity you’re measuring as time passes. On a line graph, time is usually the independent variable on the x-axis (the cause you’re observing changes in), while the thing you record—the temperature, height, population, or any other quantity—fills the y-axis. This measured quantity depends on time, so it’s the dependent variable. The slope of the line would tell you the rate of change, not what the axis represents, and a constant would just produce a horizontal line without changing that the y-axis is the measured quantity.

The y-axis shows the quantity you’re measuring as time passes. On a line graph, time is usually the independent variable on the x-axis (the cause you’re observing changes in), while the thing you record—the temperature, height, population, or any other quantity—fills the y-axis. This measured quantity depends on time, so it’s the dependent variable. The slope of the line would tell you the rate of change, not what the axis represents, and a constant would just produce a horizontal line without changing that the y-axis is the measured quantity.