Which plot is best for showing the relationship between two quantitative variables?

• A. Circle graph
• B. Line graph
• C. Scatter plot
• D. Bar graph

Answer: (C)

To see how one numerical variable relates to another, use a scatter plot. Each point represents a pair of measurements, so you can quickly spot the overall pattern: whether the variables tend to move together (positive or negative association), whether the relationship looks linear or curved, and where data clusters or outliers lie. This format directly maps one variable to the x-axis and the other to the y-axis, making the relationship visible at a glance. Other plots have different strengths: line graphs highlight changes over time or sequence, bar graphs compare quantities across categories, and circle graphs show parts of a whole. Because a scatter plot displays how two quantitative variables relate to each other, it’s the best choice for this purpose.