Dear Syed,

You must read some re known research papers related to" Data sets for the effort estimation calculation" and then you will get the idea and proper way to proceed in your planned way of research. You will also get some link and hints for proceeding your research.

All the best!!

Going through the literature to see which datasets people are using would be a good idea. However, you can always use SiP dataset as well for effort estimation that is a common consideration of researchers in the domain:

https://github.com/Derek-Jones/SiP_dataset

As what Bhausaheb E. Shinde said

You should read more published papers