Statistics

The word “statistics” seems to have been derived from the Latin  word “status” or Italian “Statista” or German “Statistek”. Each of these means “Political State”. In ancient time governments used to collect the information regarding the population & property of the state.

Different authors have defined statistics differently from time to time. The reasons of a variety are primarily two –

Firstly, In modern time, the field of the study of statistics has widened considerably. In ancient time it was confined with only the affairs of the state. But now it embraces almost every sphere of human activity. Hence a number of old defⁿ s which were confined a very narrow field of enquiry where replaced by new defⁿ.

Secondly, some writers defined it as ‘Statistical data’ i.e. numerical statement of facts while others defined it as a ‘Statistical method’.

Statistical data:

            Bowly defined statistics as numerical statement of facts in any department of enquiry plaud in relation of each other.

            Connor defined, statistics are mearsurements, enumerations or estimates of nauturaql or social phenomenon, systemetically arranged so to exhibit their inner relation.

            Yule & Kendal defined, “By statistics we mean quantitive3 data effected to a marked extent by multiplicity of causes.”

Variable : The measurements of elements of a population having certain characteristics may vary from elements to element either in magnitude or in quality. These measurable characteristics are called variable. OR, A variable is a measurable quantity which can assume any of the prescribed set of values the domain of variable.

Types of variable :

            There are two types of variable :-

a)      Qualitative variable,

b)      Quantitative variable.

a)      Qualitaive variable : Which is not measured by numerical but classified on the basis of quality. i.e. colour, religion etc.

b)     Quantitative variable : A quantitative variable is measured by numerically i.e. height, weight etc.

Quantitative variable are of two types :-

a)      Discrete variable : A variable which can take only isolated value is called a discrete variable or which can take only integral values is called Discrete variable.

Ex – 1. The number of children in a family.

        2. The number of students in a class.

b)  Contunuous variable : A variable whidh can assume any value within a certain range is called a contunous variable.

     Ex – 1. Height of a person.

             2. weight of the 1^st year students.