Hello dear,

Hope you are doing good. The basic difference between the primary and secondary data is that the primary data is the real time data collected by the researcher himself whereas secondary data refers to the data which is already collected by someone else for his use and you are using that data for your research purpose. The primary data is gathered from original source but the secondary data is obtained from studies or experiments.

For example : If a fire in a building injured 10 people and you visit the place to know the number of people injured then the data collected by you will be primary data but if you got to know the number of injured people through TV or newspaper and you use that data for your school project then that data will be secondary data.

Hope it helps!!