Bar Graph

Bar Graph


Bar Graph

A bar graph is a pictorial representation of data in which bars of uniform width are drawn with equal spacing between them on one x-axis depicting the variable. The value of the variable are shown on the y-axis, and the heights of the bars depend on the values of the variable.

Rules for drawing a bar graph:
a.  The events are written horizontally and the numbers are written vertically.
b.  All the bars drawn should have an equal width.
c.  Each bar is separated by an equal gap.
d.  Each bar should be colored with different colors.

Bar graphs are of two types:    i.  Simple bar graph      
         ii. Multiple bar graph

Simple bar graph:

Simple bar graph is constructed for the single component of the given data. Let us take an example of number of students and the subjects they liked in a survey among the students.

Subjects
English
Maths
Science
Social
No. of students
30
40
55
25


Simple bar graph:

Example: Simple bar graph:

From the above simple bar graph we can look for,
i.      How many students were asked the questions in the survey?
ii.     How many students like science?
iii.    Which is the most popular subject among the students? etc.

In this way, the simple bar graphs bar shows the result of a survey. The bar graph is very useful to compare the numbers of quantity of the same kind.

Multiple bar graph:

Multiple bar graph is constructed to present two or more related components of the given data. Let us take an example of number of boys and girls of different classes as given in the table below.

Classes -->
VIII
IX
X
Boys
20
10
15
Girls
15
25
10

Multiple bar graph:

Example: Multiple bar graph:

The above bar diagram shows the number of students of class VIII, IX and X. Here the number of boys and girls of each class is shown in different bar graphs. This is the example of multiple bar diagram.


Workout Examples

Example 1: Represent the following data in a simple bar diagram.

Grade
I
II
III
IV
V
No. of Bools
8
12
18
20
18

Solution: Here,
                        Simple bar diagram,

Example 1: Simple bar diagram


Example 2: The following information shows the mode of travel to school used by the students. Construct a multiple bar diagram.


Walk
School Bus
Public Bus
Bicycle
Boys
80
60
60
15
Girls
100
50
70
10


Solution: Here,
                        Multiple bar diagram,

Example 2: Multiple bar diagram


You can comment your questions or problems regarding the bar graphs here.

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