Which type of chart would be best for displaying correlations between two numerical variables?

The most suitable type of chart for displaying correlations between two numerical variables is a scatter plot. A scatter plot visually represents individual data points on a two-dimensional graph, with one variable plotted on the x-axis and the other on the y-axis. This layout allows for an immediate visual assessment of how the two variables relate to each other.

When examining a scatter plot, you can easily observe the direction and strength of the correlation. If the points trend upwards from left to right, there is a positive correlation; if they trend downwards, there is a negative correlation. Additionally, the tightness of the cluster of points around a line provides insight into the strength of the correlation.

The other chart types mentioned are not as effective for this purpose. Bar charts are best for categorical data comparisons, while line charts are used primarily for displaying trends over time. Pie charts are suited for showing parts of a whole and do not convey relationships between two numeric variables at all. Thus, for analyzing correlations specifically, the scatter plot stands out as the optimal choice.