Any data science project should be driven by business problems that means data science serves an organization by providing answers for its business problems and strategies in decision making process.
The chart below is a mapping from business problems into types of learning methods but it’s not a mapping from a specific business application to a specific scientific method. The right methods should be chosen according to a specific business problem and the end performance matric.

https://www.linkedin.com/pulse/data-science-landscape-ling-zhang