The key challenge to finding practical data analysis problems in the online domain is that the data provided in online practical sites such as Kaggle etc. are much cleaner and more manageable; whereas the data in real-world business scenario is much more complicated, unclean and unstructured. Therefore, there is no precise or absolute website or any other online source wherein students can get first-hand experience on solving practical data analysis problems.
Still, the best website to practice data analysis problem in Kaggle wherein students are recommended to formulate their own research questions; and then collect relevant data from scrapping different websites, portals, and government stats site. This would help them gain real-time experience in solving practical data problems.