Which graph is best for data with two sets and to show correlation between the two sets?

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

Answer: (B)

A scatter plot is best for showing how two numerical variables relate to each other. By putting one variable on the horizontal axis and the other on the vertical axis, each point represents an observation. This arrangement makes patterns easy to see: an upward trend means positive correlation, a downward trend means negative correlation, and a loose spread indicates little or no correlation. You can also gauge strength by how tightly the points cluster around a line.

Linear line graphs focus on how a single quantity changes over time or across a sequence, which isn’t about the relationship between two different variables. Bar graphs compare amounts across categories, which works for categorical data or separate groups but not for illustrating a relationship between two numerical sets. Circle graphs, or pie charts, show parts of a whole and don’t depict how two variables relate, so they’re not suitable for correlation analysis.