Presentation on theme: "Characteristics of Statistical Data Dr. Vijay Kumar"— Presentation transcript:
Characteristics of Statistical Data Dr. Vijay Kumar
Statistics are aggregates of facts Statistics are affected to a market extent by multiplicity causes Statistics are numerically expressed Enumerated or estimated according to reasonable standard of accuracy Statistics are collected for a pre-determined purpose Statistics are collected in a systematic manner Statistics should be placed in relation to each other
Statistics are aggregate of facts Single and isolated numerical expressions are not called statistics as such facts cannot be put in comparison or in relation to others. For eg., ‘Atual’s marks in Management are 80’ is not a statistics. But marks of 10 students in Management 35,60,54,87,67,90,55,43,77,60 are statistics. So a set or an aggregate of observations form statistics.
Usually statistical facts are not traceable to a single cause. Since statistics are most commonly used in social science it is natural that they are affected by a large variety of factors at the same time. It is usually not possible to study the effects of any one of these factors separately as in the case in experimental methods. In statistical methods the effects of various factors affecting a particular phenomena are generally studied in a combined form. Statistics are affected to a marked extent by multiplicity causes
Most of the statistics, however, are affected to a considerable degree by multiple causation. For eg., statistics of production of rice are affected by the rainfall, quality of soil, seeds and manure, method of cultivation etc. It is very difficult to study separately the effect of each of these factors on the production of rice. The same is true for statistics of prices, imports, exports, sales profits, etc.
Statistics as numerically Expressed Quantitative expressions are not statistics unless they are expressed in numerical forms. As for instance, the statement ‘students of a particular are good in Statistics’ is not a statistical statement. Similarly, the statements like ‘the exports in the country are on the increase’ & ‘the birth rate in India is decreasing’ are not statistical statements. However, the statement worthwhile that the qualitative aspects, which can be expressed numerically by assigning scores or ranks or standards, can be treated as statistics.
Enumerated or estimated according to reasonable standard of accuracy Statistics are made available by maintaining reasonable standards of accuracy. For precise results, statistics must be accurately complied. When a complete enumeration or estimation is not possible, the sampling method is adopted and a reasonable standard of accuracy is maintained in collecting, classifying and analyzing the data. It all depend upon the nature and purpose of the enquiry for which statistics to be serve.
For eg., the number of students in a class can be counted with perfect accuracy while counting the number of persons attending a political rally may be a difficult task. In the later case one has to use the estimation procedure to make statements like ‘10 thousand people attended the rally’. Here the statement does not mean exactly 10 thousand but it may be few hundred less or more.
Statistics are collected for a predetermined purpose The purpose of collecting statistical data must be decided in advance. It should be well defined and stated. Data collected in an unsystematic manner and without complete awareness of the purpose will be confusing and can not be made the basis for valid conclusions. Moreover, data not collected for predetermined purpose their usefulness would be almost negligible.
For eg., if the objective is stated to be collection of data on prices, it would not serve any useful purpose one knows whether the objective is to collect data on wholesale or retail prices and the relevant commodities in view.
Statistics are collected in a systematic manner It is essential that data must be collected in a systematic manner. Facts and figures collected in a haphazard manner would like to load a fallacious result.
Statistics should be placed in relation to each other Statistical data are collected mostly for the purpose of comparison. For the purpose of comparison it is necessary that data must be homogeneous. It would be meaningless to compare the heights of men with heights of trees because these figures are of a heterogeneous character such figures do not come under the category of statistics.
Conclusion : We may conclude from the above discussion that, “ all statistics are numerical statements of facts but all numerical statements of facts are not statistics”