The key factor in finding practical data analysis problems in the online domain is that the data provided in online practical sites such as https://www.kaggle.com etc. are much cleaner and more manageable; whereas the data in real-world business scenarios 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 in 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.
Happy learning :)