Data is usually collected in the context of a situation that we want to study. Data is represented **graphically **to give a clear idea of what it represents. It can be represented in following ways.

**1) A Pictograph: **Pictorial representation of data using symbols.

**2) A bar graph: **A display of information using bars of uniform width, their heights being proportional to the respective values.

**3) Double Bar Graph: **A bar graph showing two sets of data simultaneously. It is useful for the comparison of the data.

**Demonstration:**

The observations from the chart above.

- The bar chart given above represents the number of students in class VIII from 2003 to 2008 each year.
- In the year 2004 to 2005 there is a maximum increase in the number of students.
- Maximum number of students are present in the year 2007 to 2008