Which visualization type is typically used to display the relationship between two quantitative variables?

• A. Bar chart
• B. Scatter plot
• C. Histogram
• D. Pie chart

Answer: (B)

To see how two numeric variables relate, use a scatter plot. In a scatter plot, each axis represents one quantitative variable and every observation appears as a point at the coordinates of its values. By looking at how the points cluster and trend, you can spot the direction of the relationship (positive or negative), its strength, and whether it’s linear or nonlinear. You can also identify outliers and clusters, and even add a trend line to quantify the relationship.

Bar charts compare a categorical or discrete group against a value, not two continuous variables, so they don’t reveal how two numeric measures relate. Histograms display the distribution of a single quantitative variable, not the relationship between two variables. Pie charts show parts of a whole for categories, which again doesn’t capture a relationship between two numeric values.