### Theory:

In the previous topics, we have learnt how to present the data using tables. Now, we shall learn how to represent the data graphically. In this session, we will learn about $$3$$ graphical representation. They are:
• Bar graphs
• Histograms
• Frequency polygons
Bar graphs:
A bar graph is a pictorial representation of data which usually contains horizontal and vertical bars(say, $$x$$ axis and $$y$$ axis) whose lengths($$x$$ axis) have equal spacing between them and heights($$y$$ axis) vary according to the number of items.
Example:
Consider the following example.

In a school, the number of students in a classroom are given below:

 Standards Number of students $$VI$$ $$30$$ $$VII$$ $$42$$ $$VIII$$ $$35$$ $$IX$$ $$38$$ $$X$$ $$26$$

Draw a bar graph for the above data.

Solution:

Step $$1$$: Draw horizontal and vertical lines and name the horizontal axis as standards and the vertical axis as Number of students. The scale of the vertical axis is $$1$$ unit $$= 5$$ students and the horizontal axis we take equal lengths for all bars and maintain the same gap between them.

Step $$2$$: For standard $$VI$$, let us draw a rectangular bar of equal length and height of $$30$$ units.

Step $$3$$: Similarly, we can draw the other standards of equal gap of $$1$$ unit between them.

Therefore, the bar graph for the given data is: