What are (1) primary data (2) secondary data?

Question:
What are (1) primary data (2) secondary data? Which of the two - the primary or the secondary data - is more reliable and why?

Solution:

The word data means information statistical data and are of two types:

(1) Primary data

When an investigator collects data himself with a definite plan or design in his or her mind is called Primary Data.

(2) Secondary Data

Data which are not originally collected rather obtained from published or unpublished sources are called secondary data.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.