Unformatted text preview: . k = 1 + 3.322 log10N
7. 15 and 25
8. width or size of class
9. Midvalue
10. Frequency
67 5. DIAGRAMATIC AND GRAPHICAL
REPRESENTATION
5.1 Introduction:
In the previous chapter, we have discussed the techniques of
classification and tabulation that help in summarising the collected
data and presenting them in a systematic manner. However, these
forms of presentation do not always prove to be interesting to the
common man. One of the most convincing and appealing ways in
which statistical results may be presented is through diagrams and
graphs. Just one diagram is enough to represent a given data more
effectively than thousand words.
Moreover even a layman who has nothing to do with
numbers can also understands diagrams. Evidence of this can be
found in newspapers, magazines, journals, advertisement, etc. An
attempt is made in this chapter to illustrate some of the major types
of diagrams and graphs frequently used in presenting statistical
data.
5.2 Diagrams:
A diagram is a visual form for presentation of statistical
data, highlighting their basic facts and relationship. If we draw
diagrams on the basis of the data collected they will easily be
understood and appreciated by all. It is readily intelligible and save
a considerable amount of time and energy.
5.3 Significance of Diagrams and Graphs:
Diagrams and graphs are extremely useful because of the
following reasons.
1. They are attractive and impressive.
2. They make data simple and intelligible.
3. They make comparison possible
4. They save time and labour.
5. They have universal utility.
6. They give more information.
7. They have a great memorizing effect.
68 5.4 General rules for constructing diagrams:
The construction of diagrams is an art, which can be acquired
through practice. However, observance of some general guidelines
can help in making them more attractive and effective. The
diagrammatic presentation of statistical facts will be advantageous
provided the following rules are observed in drawing diagrams.
1. A diagram sh...
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 Winter '08
 Moshiri
 Business, Statistics

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