Answer: A lot!
To even study Data Science, you need start off being a mathematician/statistician, which means you need a very solid foundation in university mathematics, starting with the following undergraduate, lower-division courses:

You may have searched around the internet looking for math/calculus-level courses to build up your math skills in preparation for Data Science. There certainly are excellent (free!) courses online via MOOCs (Massive Open Online Courses). However, you will want to have all of the above courses on real, transferable Academic transcripts to prove you have completed these courses, with letter grades, not just say "I took these courses from a MOOC". You need real credentials as a mathematician for data science.

MOOCs (Massive Open Online Courses) are awesome, but they do not provide real academic course credit for their courses. If you plan to go for a B.A. or M.A. with a Data Science concentration, you will not be able to say "Oh, I took all my calculus courses from a MOOC" - you need these courses in your academic portfolio.

We invite you to explore our Distance Calculus courses in more detail via the links above, or perhaps the movies below.

Data Science & Distance Calculus

Academic Credits from Distance Calculus

Distance Calculus - Student Reviews

Date Posted: Feb 19, 2020
Review by: Rebecca Johnson
Courses Completed: Applied Calculus
Review: I took the Business Calculus course from Distance Calculus in 2013. I was admitted to my MBA program, but then they told me I needed to take Calculus before starting the program. I finished the Business Calculus course in about 3 weeks in August before my program started. Not the most fun thing to do over the summer, but at least I got it done. Thanks Diane and Distance Calculus team!
Transferred Credits to: Kellogg MBA Program

Date Posted: Jan 13, 2020
Review by: Janice Flores
Student Email: jflores35@knights.ucf.edu
Courses Completed: Calculus II
Review: I highly recommend this course! Dr. Curtis is the best teacher and is ALWAYS willing to work with you to make sure you understand the subject. It was definitely a positive experience and the credits were transferred to my University with no problems! I definitely do not regret it and I had doubts in the beginning but if I had to, I would do it all over again!
Transferred Credits to: University of Central Florida

Date Posted: Aug 23, 2020
Review by: Sean Metzger
Student Email: seanmetzger78@gmail.com
Courses Completed: Differential Equations
Review: A lifesaver. When I found out I needed a course done in the last weeks of summer I thought there was no way i'd find one available, but this let me complete the course as quickly as I needed to while still mastering the topics. Professor always got back to me very quickly and got my assignments back to me the next day or day of. Can't recommend this course enough for students in a hurry or who just want to learn at their own pace.
Transferred Credits to: Missouri University of Science and Technology