data collection in statistics(one topic)

Course

HISTORYO The History of statistics  can be

said to start around 1749 although, over time, there have been changes to the interpretation of the word statistics. In early times, the meaning was restricted to information about states. In modern terms, "statistics" means both sets of collected information, as in national accounts and temperature records, and analytical work which requires statistical inference.

DEFINITIONO Statistics is the sciences and art of

dealing with figures and facts.O Statistics is well defined as

collection, presentation, analysis and interpretation of numerical data collected from different sources.

MY TOPIC

STATISTICAL DATAO A sequence of observation, made on

a set of objects included in the sample drawn from population is known as statistical data.

DATA TYPESUN-GROUPED

DATA:GROUPED

DATA:O Data which have

been arranged in a systematic order are called raw data or ungrouped data.

O Data presented in the form of frequency distribution is called grouped data.

DATA COLLECTIONO The first step in any investigation is

collection of data. The data may be collected for the whole population or for a sample only. It is mostly collected on sample basis. Collection of data is very difficult job. The investigator is the well trained person who collects the statistical data. The respondents are the persons from whom the information is collected.

What methods should be used to collect data?

The selection of a method for collecting information must balance several concerns including

O Resources must be availableO Analysis and reportingO Relevant studyO And the skill of the evaluator

Classification of data

Both types are further explained below:

PRIMARY DATAO The primary data is the first hand

information collected , compiled and published by organization for some specific purpose. They are most original data and have not yet have gone under any statistical treatment.

e.g. Population census reports are primary data because these are collected, complied and published by the population census organization.

METHODSO Personal Investigation: The researcher

conducts the survey and collect data from it. This data is usually accurate and more reliable.

O Through Investigation: Trained investigators are employed to collect the data. This data is collected by contacting individuals and by filling questionnaire. This is most popular method.

O Collection Through questionnaire:The researchers get the data from local representatives that are based upon their own experience. This method is quick but only rough estimate.

O Through Telephone: The researchers get information through telephone this method is quick and give accurate information but is expensive.

SECONDARY DATAO The secondary data are the second

hand information which are already collected by some organization for some purpose and are available for the present study. The secondary data are not pure in character and have undergone some statistical treatment at least once.

e.g. Economics survey of a country is secondary data because these are collected by more than one organization like Bureau of statistics, Board of Revenue, the Banks etc…

METHODSO Official: e.g. employee’s in a bank, Ministry

of finance, Ministry of food, labor etc….

O Semi –Official: e.g. State Bank, Railway Board, Central Cotton Committee, Boards of Economic Enquiry etc….

O Technical and trade Journals and Newspapers.

O Research Organizations such as Universities and other institutes.

To understand the concepts easily let us take an example.

e.g. Suppose we are interested to find the average age of MS students. We collect the

age’s data by two methods; either by directly collecting from each student himself

personally or getting their ages from the university record. The data collected by the

direct personal investigation is called primary data and the data obtained from the university record is called secondary data.

FOR BETTER UNDERSTANDING

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