Spaceage

Hi folks - Would anyone be able to shed some light on the types of questions being asked in the digital interview for the MS programs at Columbia Fu? The questions may vary by program/department, but I have a hunch that they are similar. Thanks

1)  You can learn the basics of Python just by doing Code Academy, edX, or one of the free online course providers. I have found personally, however, that the best way to learn programming, software packages, etc. is to use them regularly. I had limited experience with LaTeX and R before graduate studies, but I was able to pick up on them fairly quickly just by using them regularly.
2) For research opportunities, you will have to ask a professor if you can work as their Research Assistant.
3) A Masters in Statistics or a Masters in Computer Science gives you ample opportunities in industry. A PhD might be preferred for some of the bigger companies like Google and Microsoft, but you  can still get a decent job in Data Science/ML with just a Masters, sometimes with only a Bachelor's if you get the right experience. I have a friend who only has a Bachelor's in Biochemistry but now he's the Head of Data Science & Engineering for a health care startup. To the best of my knowledge, he got his first job as a data scientist out of college (no graduate degree), but he had to teach himself how to be a good "hacker" (Python, R, etc.) to get that job. After he had the relevant experience, his academic credentials didn't really matter.
I wouldn't say that getting a PhD is necessary to become a data scientist if you are a U.S. citizen (the bar is higher for non-citizens -- if they want to work in industry in the U.S., a PhD often makes it easier for them to get these jobs). You can get by with only a Masters and sometimes only a Bachelor's. Only do the PhD if you think you will like doing academic research.

It's hard to imagine you could really know you want a PhD in a quantitative subject when you haven't really taken any math classes to know what that entails - but let's assume for a second that you do.  You might be able to get into a PhD program by just taking a few more classes.  If you took through Calc 3, linear algebra, and a probability class, you'd be a decent candidate for a lower tier but respectable biostatistics PhD.  There is almost zero chance of you getting into a math or CS PhD without literally completing almost an entire bachelor's degree.  My advice would be to take a couple of these classes and see what really interests you about them and evaluate how much time you're willing to put into that - but biostatistics is the clearest path open to you.
 
I would also second the advice that a master's (after the math pre reqs) might be a very good idea for you.

Hi there. First of all, is there a reason why you want to jump straight into a Ph.D.? Given your background, it might be more efficient to complete a Master's in CS/Stats/related fields. I have heard that some of these programs like having applicants from industry and other academic backgrounds. Then if you still want the Ph.D., you will be in a much better situation to apply for top programs. 
If you do prefer to get another Bachelor's, I can offer some advice on that. I don't think that being out of school for three years will significantly affect your chances in a negative way. But I think you will have to gain some research experience, like all applicants (traditional background or not), before being admitted to top Ph.D. programs. Moreover, it would be good to ensure that you like research, before committing to a five year Ph.D. program. It's not necessarily a problem that your school has limited research opportunities, since you can find research opportunities elsewhere (you can apply for summer NSF-REUs, government internships through NIH, U.S. Census Bureau, DOE labs, etc., although it might be difficult to get these positions until after more than 2 semesters of coursework...). But keep in mind that pursuing a Ph.D. typically means a willingness to move anywhere for the best research and career opportunities, so staying in NYC might restrict your options. Also if your school has limited ongoing research in general (meaning that there are few researching professors and graduate students) then you may consider attending a better school. Unfortunately, the rankings of an undergraduate institution do matter to some extent in graduate applications (Bs at MIT probably count more than As at an unknown school).