Diagramatic Representation of Data
Diagrams are advance technique to present the data. As a layman, one cannot
understand the tabulated data easily but with only a single glance at the
diagram, one can gets complete picture of data.
Types of Diagrams:
Diagrams can be classified in the following categories:
(i). One-dimensional Diagrams
(ii). Two-dimensional Diagrams
(iii). Three-dimensional Diagrams
(iv). Pictograms
(v). Cartograms
(i). One-dimensional
Diagrams:
In this case only we consider length dimension. These
diagrams either Bar or Line Diagrams.
Merits:
1. These are very easy to construct
2. These are easy to understand
3. Comparison can be made easily.
A) Line Diagrams: In these diagrams only line is
drawn to represent one variable. These lines may be vertical or horizontile.
The lines are drawn such that their length is in proportion to the value of the
variable or item.
Ex: No of accidents in a city in a year given below.
|
Month |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
|
No. of Accidents |
8 |
12 |
20 |
16 |
10 |
16 |
20 |
14 |
10 |
19 |
16 |
10 |
B) Simple Bar Diagram: Like line diagrams these figures are
also used where only single dimension i.e. length can present the data.
Procedure is almost the same, only the thickness of lines is measured. These
can also be drawn either vertically or horizontally. Breadth of these lines or
bars should be equal. Similarly distance between these bars should be equal.
Ex: Average Wage Of A Particular Firm Has Given Below. Represent
it by Bar Diagram
|
Farm |
A |
B |
C |
D |
E |
F |
|
Average Wage |
345 |
598 |
540 |
305 |
190 |
150 |
C). Multiple Bar
Diagrams: This
diagram is used, when we have to make comparison between more than two variables.
The number of variables may be 2, 3 or 4 or more. In case of 2 variables pair
of bars is drawn. Similarly, in case of 3 variables, we draw triple bars. They
are drawn on the same proportionate basis as in case of simple bars.
Ex: No. of students in Postgraduate classes in a university
is below:
|
|
Science |
Humanities |
Commerce |
|
2020-21 |
560 |
240 |
220 |
|
2021-22 |
610 |
280 |
280 |
|
2022-23 |
820 |
340 |
370 |
D).
Sub-divided Bar Diagram: More than
one variable data through this diagram like multiple bar diagram. In this case
we add different variables for a period and draw it on a single bar as shown in
the following examples. The components must be kept in same order in each bar.
This diagram is more efficient if number of components is less i.e. 3 to 5.
Ex: Production of grains in Andhra Pradesh is as follows.
Present the data by a sub-divided diagram.
|
|
Wheat |
Maize |
Paddy |
|
2020-21 |
8000 |
4000 |
12000 |
|
2021-22 |
9000 |
6000 |
11500 |
|
2022-23 |
8500 |
6000 |
13000 |
E). Percentage Bar
Diagram: Like
sub-divided bar diagram, in this
case also data of one particular period or variable is put on single bar, but
in terms of percentages. Components are kept in the same order in each bar for
easy comparison.
Ex: Present the given data by percentage bar diagram
|
|
Arts |
Science |
Commerce |
|
2020-21 |
600 |
400 |
250 |
|
2021-22 |
550 |
600 |
400 |
|
2022-23 |
500 |
800 |
450 |
(ii). Two Dimensional
Diagrams
As in single bars it was mentioned that the width of each bar
should be equal for a certain variable or items. But in this case not only the
length but the width also is taken proportionately in case of rectangles.
A) Rectangles: Here we have to consider both length and breadth or width of
each item is in proportion.
Ex: Present the given data by rectangular diagram
|
|
Arts |
Science |
Commerce |
Total
|
|
2020-21 |
280 |
170 |
150 |
600 |
|
2021-22 |
310 |
220 |
270 |
800 |
|
2022-23 |
360 |
300 |
340 |
1000 |
Ex: Present the given data by rectangular diagram
|
Expenditure Items |
Family A |
Family B |
|
Food |
3300 |
4500 |
|
Clothing |
1080 |
1080 |
|
Fuel |
300 |
450 |
|
Rent |
720 |
900 |
|
Education |
480 |
900 |
|
Misc |
420 |
720 |
B) Squares: As told earlier, this technique can
be used effectively when given items terms are squares, preferably having two
zeros (00) after every term. Here we take square root of every item and then
divide it by a suitable digit or number so as to get the size reduced to be put
into the shape of a square on the given space. It is also, useful technique
when difference between the numbers is large.
Ex: Following is the
population of some cities in thousands. Present by a suitable diagram.
|
City |
Population (in '000) |
|
Mumbai |
3600 |
|
Calcutta |
2500 |
|
Chennai |
1600 |
|
Delhi |
900 |
|
Andhra Pradesh |
400 |
C). Circular Diagrams:
As like in squares, the items are squared and differences
between the terms is also large then we may represent the data in circles.
Ex: Following is the
population of some cities in thousands. Present by a suitable diagram.
|
City |
Population (in '000) |
|
Mumbai |
3600 |
|
Calcutta |
2500 |
|
Chennai |
1600 |
|
Delhi |
900 |
|
Andhra Pradesh |
400 |
D). Sub-divided
Circular Diagrams:
These are also called Pie or Angular diagrams.
Ex: Present the following data through pie-chart
|
Items |
Expenditure(In Rs) |
|
Food |
5100 |
|
Clothing |
1200 |
|
Education |
750 |
|
Recreation |
500 |
|
Misc. |
75 |
|
Total |
7625 |
