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 xaxis depicting the variable. The value
of the variable are shown on the yaxis, 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:
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

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