The word data means information statistical data and of two types
(i) Primary data,
(ii) Secondary data
(i) Primary data: when an investigator collects data himself with a definite plan or design in his (her) mind is called primary data
(ii) Secondary data: data which are not originally collected rather obtained from published or unpublished sources are known as secondary data. Secondary data are collected by an individual or an institution for some purpose and are used by someone else in another context
Primary data are reliable and relevant because they are original in character and are collected by some individuals or by research bodies.
