Data is a collection of facts and measurement.
Data is a tool which helps in reaching a sound conclusion by providing information therefore. For statistical investigation, collection of data is the first and foremost.
Sources of Data
1. Primary Source
2. Secondary Sources
a. Published sources
b. Un-published sources
Primary Data– Data originally collected in the process of investigation are known as primary data. This is original form of data which are collected for the first time.It is collected directly from its source of origin.
Methods of collecting primary data
There are three basic ways of collecting data :
(i) Personal interview OR Direct Personal Investigation
(ii) Mailing (questionnaire surveys)
(iii) Telephone interviews
(iv) Indirect verbal investigation
(v) Information from local sources
(vi) Enumerator method
Secondary data It refers to collection of data by some agency, which already collected the data and processed. The data thus collected is called secondary data.
Point of difference between Primary and Secondary data :-
4. Need of modification