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Unformatted text preview: e frequency of occurrence of different values
of a single Phenomenon.
A frequency distribution is constructed for three main reasons:
1. To facilitate the analysis of data.
2. To estimate frequencies of the unknown population
distribution from the distribution of sample data and
3. To facilitate the computation of various statistical
4.2 Raw data:
The statistical data collected are generally raw data or
ungrouped data. Let us consider the daily wages (in Rs ) of 30
labourers in a factory.
80 70 55 50 60 65 40 30 80 90
75 45 35 65 70 80 82 55 65 80
60 55 38 65 75 85 90 65 45 75
The above figures are nothing but raw or ungrouped data
and they are recorded as they occur without any pre consideration.
This representation of data does not furnish any useful information
and is rather confusing to mind. A better way to express the figures
in an ascending or descending order of magnitude and is commonly
known as array. But this does not reduce the bulk of the data. The
above data when formed into an array is in the following form:
30 35 38
60 60 65
75 75 75 40
90 The array helps us to see at once the maximum and
minimum values. It also gives a rough idea of the distribution of
the items over the range . When we have a large number of items,
the formation of an array is very difficult, tedious and cumbersome.
The Condensation should be directed for better understanding and
may be done in two ways, depending on the nature of the data.
a) Discrete (or) Ungrouped frequency distribution:
In this form of distribution, the frequency refers to discrete
Here the data are presented in a way that exact
measurement of units are clearly indicated.
There are definite difference between the variables of
different groups of items. Each class is distinct and separate from
the other class. Non-continuity from one class to another class
exist. Data as such facts like the number of rooms in a house, the
number of companies registered in a country, the number of
children in a family, etc.
The process of prepa...
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This note was uploaded on 01/18/2014 for the course BUS 100 taught by Professor Moshiri during the Winter '08 term at UC Riverside.
- Winter '08