Custom graphs offer the possibility to construct three kinds of graphs: XY, pie, and bar charts. When should I use each type?
First, read over the answers to the FAQs about how to construct the three kinds of graphs. Each begins with a simple definition of the graph type. In general, bar charts are appropriate for comparing two to ten categories that can be measured numerically; pie charts are appropriate for comparing percentages of a whole; and XY charts show the relationship, or correlation, between two numerical variables.