The basis of statistics consists of numbers or observations usually obtained by some process of counting or measurement.
These are collectively as data. Data may be of two broad types : Primary data and Secondary data.
Primary data: Data collected primarily for the purpose of the given enquiry are called primary data.
Secondary data: The ordinary user of economic and social statistics will find that the data have been already collected by some other agency. His job will then be simply to have access to the source and get hold of the data. Such data will be called Secondary data.