This document provides information about different types of graphs used to represent data visually. It discusses primary and secondary data, and defines a graph as a diagram that shows relationships between numbers. The main types of graphs covered are bar graphs, double bar graphs, and pictographs. Bar graphs represent data using bars of equal width, while double bar graphs show two sets of data simultaneously for comparison purposes. Pictographs use symbols to pictorial represent data. Examples of each graph type are provided to illustrate their structure and use.