The word statistics has several meanings. In the first place, it is a plural noun which describes a collection of numerical data such as employment statistics, accident statistics, population statistics, birth and death, income and expenditure, of exports and imports etc. It is in this sense that the word 'statistics' is used by a layman or a newspaper.
Secondly the word statistics as a singular noun, is used to describe a branch of applied mathematics, whose purpose is to provide methods of dealing with a collections of data and extracting information from them in compact form by tabulating, summarizing and analyzing the numerical data or a set of observations.
The various methods used are termed as statistical methods and the person using them is known as a statistician. A statistician is concerned with the analysis and interpretation of the data and drawing valid worthwhile conclusions from the same.
It is in the second sense that we are writing this guide on statistics.
Lastly the word statistics is used in a specialized sense. It describes various numerical items which are produced by using statistics ( in the second sense ) to statistics ( in the first sense ). Averages, standard deviation etc. are all statistics in this specialized third sense.
The word ’statistics’ in the first sense is defined by Professor Secrit as follows:-
"By statistics we mean aggregate of facts affected to a marked extent by multiplicity of causes, numerically expressed, enumerated or estimated according to reasonable standard of accuracy, collected in a systematic manner for