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INTRODUCTION OF FREQUENCY DISTRIBUTION

__FREQUENCY
DISTRIBUTION –__

**INTRODUCTION
–**

**In various
fields, we need information in the form of numerical figures which is to be called
or considered as data. These data may be related to the marks obtained by the
pupils of a class in a certain examination; the weights, heights, ages, and
many more, of pupils in a class, the monthly wages earned by workers in a factory,
the population of a city, or the profits of a company during last few years, marks
obtained by students in a class or school, etc. Evaluation of such data helps
analysts study the various growth patterns and formulate future targets or
policies or derive certain inferences.**

**Data **–

**The word
“data” means a set of given or obtained facts in numerical figures. It is only data.**

**Statistics
**–

**It is the
science which deals with the collection, presentation, analysis, and
interpretation of numerical data where analyst can make the future planning or strategy.
In singular form, statistics is taken as a subject and in plural form,
statistics means data.**

**Fundamental
Characteristics of Data** –

**i) Numerical
facts alone form data. Qualitative characteristics, like honesty, poverty,
etc., which cannot be measured numerically and in a single word it is
impossible to present as data because these does not form any data.**

**ii) Data
are aggregate of facts, we need to take various facts from various condition of
same incidence. A single observation does not form data.**

**iii) Data
collected for a definite purpose may not be suitable for another purpose.**

**Types of Data –**

**i) Primary
Data – The data collected by the investigator himself with a definite plan in
mind are known as “primary data”.**

**ii) Secondary
Data – The data collected by someone, other than the investigator, are known as
“secondary data”**

**Variable
**–

**A quantity
which can take different values obtained from different objects of a same or
different class is called a variable. Examples : Height, age, and weight of
pupils in a class are three variables. If we denote them by x, y, are z
respectively, then values of x give the heights of the pupils, the values of y give
the ages of the pupils and the values of z give the heights of the pupils.**

**Continuous
and Discrete Variables** –

**Variables
are two types :**

__i) Continuous
Variable__ – A variable which can take any numerical value within a certain range
is called a “continuous variable”.

**Examples – a) Wages of
worker in a factory**

** b) Heights of people in a
group**

** c) Commission of employee in a office**

** d) Weight of student in a
class**

__ii) Discontinuous
(or Discrete) variable__ : A variable which cannot take all possible values
between two given values, is called a “discontinuous or discrete” variable.

** a)
Number
of members in a family**

** b)
Number
of workers in a factory**

** Such variables cannot
take any value between 1 & 2, 2 & 3, etc.**

**Important
Terms –**

**Range **: **The difference between the maximum
and minimum values of a variable is called its range.**

**Variate** : **A particular value of a variable is called
“variate”**

**Presentation
of Data** : **Putting
the data in condensed form in the form of a table, is known or considered as
“presentation of data”**

**Frequency** : **The number of times an
observation occurs or happens is called its “frequency”.**

**Frequency
Distribution** : **The
tabular arrangement of data showing the frequency of each observation is called
its “frequency distribution”.**