Page 137 - DLIS401_METHODOLOGY_OF_RESEARCH_AND_STATISTICAL_TECHNIQUES

Methodology of Research and Statistical Techniques

Notes
60–64 IIII IIII I 11
55–59 IIII IIII III 13

50–54 IIII III 8
45–49 IIII IIII 10
40–44 IIII III 8
35–39 IIII II 7
Total 120

Procedure for Writing the Class Intervals
At the top we write the first class interval which is 95 – 99. Then we find the second class
interval by substracting 5 points from the corresponding figures i.e., 90 – 94, and write it
under 95 – 99. On substracting 5 from 90- 94, the third class interval will be 85 – 89. The
procedure is to be followed till we reach the class interval having the lowest score.
Procedure for Marking the Tallies
Let us take the first score in the first row i.e., 71. The score of 71 is in the class interval 70 –
74 (70, 71, 72, 73, 74) so a tally (/) is marked against 70 - 74. The second score in the first row
is 85, which lies in the class interval 85 - 89 (85, 86, 87, 88, 89), so a tally (/) is marked against
86 – 89. Similarly, by taking, all the 120 scores, tallies are put one by one. While marking the
tallies, put your finger on the scores, as a mistake can reduce the whole process to naughlt.
The total tallies should be 120 i.e., total number of scores. When against a particular class
interval there are four tallies (////) and you have to mark the fifth tally, cross the four tallies
(////) to make it 5. So while marking the tallies we make the cluster of 5 tallies. By counting
the number of tallies, the frequencies are recorded against each of the class intervals. It completes
the construction of table.
In Table 9.4, the exact limits of class interval 95 - 99 are 94.5 and 99.5, as the score of 95 ranges
from 94.5 to 99.5 and the score of 99 ranges from 98.5 to 99.5, making the exact range from
(94.5 to 99.5. As discussed earlier the data are continuous based on the nature of the variable.
The class interval, though customarily arranged in descending order, can also be arranged in
ascending order.

9.2 Graphical Presentation of Data

Most people show lack of interest or have no time to go through facts and figures given in a
daily newspaper or a magazine. But if these figures are graphically presented, they become
easier to grasp and catch the eye and have a more lasting effect on the reader’s mind.
The graphical representation of data makes the reading more interesting, less time-consuming
and easily understandable. The disadvantage of graphical presentation is that it lacks details
and is less accurate. In our study, we have the following graphs:
1. Bar Graphs

2. Pie Charts
3. Frequency Polygon
4. Histogram
Bar Graphs
This is the simplest type of graphical presentation of data. The following types of bar graphs
are possible: (a) Simple bar graph (b) Double bar graph (c) Divided bar graph.

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