Which chart can be used to display several variables at once or the same variable across different categories?

The polygon or line chart is particularly effective for displaying several variables simultaneously or illustrating the same variable across different categories. This capability arises from its design, which allows for multiple lines to be plotted on the same graph, each representing a different variable or category. For example, you can show trends over time for multiple data sets, allowing for quick visual comparisons of patterns and relationships among the variables.

In contrast, other chart types have limitations in this area. A bar chart typically displays one variable across different categories, which could limit its effectiveness for showing multiple variables together. A Pareto chart is a specialized bar chart that highlights the most significant factors among a set of variables but is focused on a single variable's impact, rather than comparing multiple variables at once. A pie chart primarily shows the proportion of parts to a whole, making it unsuitable for displaying multiple variables across categories or viewing trends over time.