All of the class materials and lectures for Harvard's data science course are made freely available online, so they can be studied at your own pace. You may not end up with a degree from one of the world's most prestigious universities, but the course is detailed and technical enough to make an expert of you by the end. The course is part of a data science degree and constructed for students who have prior knowledge of, or are also studying, core fields such as programming, maths, and statistics. However, there are enough free resources out there on those subjects to make this a viable option for those outside of academia, if you are dedicated enough.