Admission to Master's degree in Data Science without a STEM Background? I became really interested in data during my 2nd year of college (I’m currently in my third year) and I recently began to think that undergoing a masters degree in data science can greatly help me study the field more professionally. 

However I am not majoring in any STEM degree in my university right now (I’m an Economics major) And I’m very likely to graduate without any changes. 

I’ve heard that people from very different backgrounds who have nothing to do with STEM are often successfully admitted to data science graduate programs, but how do people from a non-STEM background get admitted when all the requirements I’ve been reading in various university websites state that if you are from a non-STEM undergraduate background you need to prove in a different way somehow that you are ready (in terms of mathematics, statistics, etc) to undertake the program?

In other words, my question is this: How do people who have non-STEM bachelor’s degrees get accepted into these programs? Is there a really a certain way to prove your analysis capabilities besides your degree for non-STEM undergraduate students that can convince the admissions committees? If you know anything about this I would sincerely appreciate it if you could share your knowledge/experience and offer helpful advice.

I’m not thinking of phD (not planning to stay in academia for that long, I simply wish to study this field a bit deeper to the point where I can apply it professionally) so hope you can consider this as well when replying :)
You said that you were studying Economics, wouldn't that be considered a STEM area (or at the very least, certain segments of Economics). I know that for instance, financial economics have been considered a STEM subject by certain institutions (e.g. Columbia)

Having that said, it really depends on the program that you are applying to. I've seen people from a broad spectrum of backgrounds enter into what would traditionally been known as quantitative sciences. I've seen psychologist and linguists working at an engineering departments for instance. What I would do is to consult the person in charge of the program that you are interested in, and ask about the specific requirements. From your own perspective, it would certainly help to take on additional courses that deal with data science so you have some experience with it, even if your primary degree isn't in a "STEM" field.