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- Statistics

Meaning of statistics

The word 'Statistics' is used in two senses-Plural and Singular. In its plural form it refers to the statistical data collected in a systematic manner with some definite aim or object in view. In singular form, it means statistical methods or the subject itself It includes the methods and principles concerned with collection, analysis and interpretation of numerical data.

 

Definitions of statistics

Different authors have given different definitions of Statistics in two different senses viz. plural and singular. Some of the definitions are given below.

Statistics, in plural sense

1.     "Statistics are numerical statement of facts in any department of enquiry placed in relation to each other"-A.L. Bowley.

2.     "Statistics are the classified facts representing the conditions of the people in a state ... specially those facts which can be stated in numbers or in tables of numbers or in any tabular or classified arrangement. "-Webster.

3.     "By statistics we mean aggregate of facts affected to a marked extent by multiplicity of causes, numerically expressed, enumerated or estimated according to a reasonable standards of accuracy, collected in a systematic manner for a predetermined purpose and placed in relation to each other."­Horace Secrist.

In plural sense Horace Secrist's definition seems to be the most exhaustive.

Statistics in singular sense

In singular sense, different authors have defined Statistics differently.

 

1.     "Statistics may be called the science of counting."-A.L. Bowley.

2.     "Statistics may rightly be called the science of averages."-A.L. Bowley.

3.     "Statistics is the science of measurement of social organism, regarded as a whole in its manifestations"-A.L. Bowley.

4.     "Statistics may be defined as the science of collection, presentation, analysis and interpretation of numerical data."-Croxton and Cowden.

5.     "Statistics may be regarded as a body of methods for making wise decisions in the face of uncertainity"-Wallis and Roberts.

 

FUNCTIONS OF STATISTICS

 

We find today that there is hardly a phase of human activity which does not find statistical techniques useful. The ever growing usefulness of Statistics is due to the functions it performs. Some of the most important functions of Statistics are

(i)     The complex mass of data are made simple and understandabtle with the help of statistical 'methods,    

(ii)    To interpret the various characterstics of data, classification is done by the application of improved techniques of Statistics.

(iii)    To study-relationship between two or more phenomena statistical methods are used.

(iv)   Statistics provides various informations in analysis of data that enlarges individual experience.

(v)    Statistics helps in formulating policies in different fields.

(vi)   Statistical methods are highly useful tools in analysing the past data and predicting future trends.

(vii)   Statistics helps us to arrive at any correct and dependable conslusion.

(viii)  Statistics helps in decision making in the face or uncertainity.

(ix)   The correctness of the laws of the different branches of knowledge can only be tested with the help of Statistics.

(x)    One important function of Statistics is to provide techniques for making comparisons.

 

Scope and importance of statistics

It is very difficult to describe clearly and-concisely the importance of any particular subject. Statistics being a comprehensive science, it has its application 'to almost all the branches of human knowledge and therefore it becomes more difficult to describe its scope. Even in our day-to-day life we apply statistical methods knowingly or unknowingly. Starting as a science of king now it has covered all branches of science viz. social, physical and natural, The physical sciences do not benefit as much from Statistics as social sciences.

It would be pointless to try to mention all the areas in which statistical methods are used. To mention only a few, Statistics is becoming increasingly important in Agricul­ture, Business and Commerce, Economics, Astronomy, Biology, Engineering, Medical, Meterology, Physics, Psychology, Sociology, Insurance, Operations Research, Com­puter Programming, Disaster Management, Demography, Actuarial Science and so on. The use of statistical methods in each of these fields grew in a different way. Statistics is not at the same stage of development in all the different fields of study.

Limitations of statistics

The field of Statistics,' though widely used in all areas of human knowledge and widely applied in a variety of disciplines, it has its limitations. It cannot be applied to all situations. Some of the limitations are

(i)     Statistics deals only with aggregates and no importance is given to individual items.

(ii)    Statistics studies only quantitative characteristics and does not study qualitative characteristics.

(iii)    Laws of Statistics, are true on an average

(iv)   Statistical results are only approximately correct.

(v)    Statistics does not reveal the entire story rather it is a helping hand.

(vi)   Statistics can be misused and hence should be applied only by experts.

 

Statistical population and sample

By Population we generally mean human population but in Statistics population is the aggregate of some individuals or objects, under study. It is also called Universe. A population may be finite or infinite depending upon the number of elements in it. For example, population of students in a class is finite whereas the population of sand particles in a river beach is infinite. Again a population may be real or hypothetical. For example, population of books in bookstall is real whereas the population of outcomes of a die throwing many a number of times is hypothetical.

The number of units in a population is called population size.

A Sample is a small representative part taken from the population to know the characteristic of the population under study. The number of units in a sample is called its sample size. For example to know the average height of 100 students, if we select 5 students and by measuring them infer about the average height of 100 students, then 5 students constitute a sample.

 

Census and sampling

If information is collected from each and every individual of a population, the method of collecting information is known as census. For example after every ten years population census is conducted where every household is examined.

Again, if information is carried out on a properly selected representative sample, the method of collecting information is known as sampling. Thus, sampling is a technique which enables to draw inferences about the entire population simply by studying a few of them. 0dmpling requires less time, labour and money and hence it is more economical than census. 

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