This document discusses various methods for diagrammatic and graphical representation of statistical data. It describes one-dimensional, two-dimensional, and three-dimensional diagrams as well as pictograms and cartograms. Specific diagram types discussed include line diagrams, bar diagrams, pie charts, and histograms. Graphical representations like line graphs, frequency polygons, frequency curves, and cumulative frequency curves are also covered. The key differences between bar diagrams and histograms are highlighted.