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Quantitative Techniques – I

Notes Similarly, there can be a two-way and multi-way classification of the data. For example, if
the students of a class are classified on the basis of their marks in statistics, we get a one-
way classification. However, if these students are simultaneously classified on the basis of
marks in statistics and marks in economics, it becomes a two-way classification.
It should be noted here that in a two-way classification, it is possible to have simultaneous
classification according to an attribute and a variable. For example, the classification of
students of a class on the basis of their marks in statistics and the sex of the person.

Did u know? The life of an electric bulb is a continuous variable that can take any value
from 0 to .

Task Write few examples of continuous variables whose actual measurements are
expressed in terms of discrete numbers.

Self Assessment

State whether the following statements are true or false:

6. When the data are classified according to geographical location or region, it is called a
geographical classification.
7. When the data are classified on the basis of its time of occurrence, it is called a chronological
classification.
8. When the data are classified according to certain conditions, other than geographical or
chronological, it is called a unconditional classification.

9. When the characteristics of the data are non-measurable, it is called a qualitative data.
10. In a one-way classification, it is possible to have simultaneous classification according to
an attribute and a variable.

2.3 Formation of a Frequency Distribution

2.3.1 Construction of a Discrete Frequency Distribution

A discrete frequency distribution may be ungrouped or grouped. In an ungrouped frequency
distribution, various values of the variable are shown along with their corresponding frequencies.
If this distribution fails to reveal any pattern, grouping of various observations become
necessary. The resulting distribution is known as grouped frequency distribution of a discrete
variable. Furthermore, a grouped frequency distribution is also constructed when the possible
values that a variable can take are large.
1. Ungrouped Frequency Distribution of a Discrete variable: Suppose that a survey of 150
houses was conducted and number of rooms in each house was recorded as shown below:
5 4 4 6 3 2 2 6 6 2 6 3 3 4 5
6 3 2 2 5 3 1 4 5 1 5 1 4 3 2
5 1 5 3 2 2 4 2 2 4 4 6 3 2 4
2 3 2 4 6 3 3 2 6 4 1 4 4 5 2

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