The document discusses different types of diagrams used to present statistical data. It describes line diagrams, bar diagrams, pie charts, and pictograms. Bar diagrams can be simple, multiple, component, or percentage. Pie charts represent data as sectors of a circle proportional to the values. Pictograms use pictures instead of bars or lines to depict amounts. Diagrams simplify complex data, create more impact, save time and labor, provide more information, and make comparisons easier compared to tables. However, diagrams only approximate values and cannot be analyzed further.