Experience needed to transition from undergrad to graduate school of two completely different majors I just graduated in May 2018 with an undergraduate bachelor degree in Computer Science from a pretty good university. During my time at the university, I always had aspirations of attending graduate school for a Masters (as a terminal degree). I had considered studying Computer Science, but during my final semester, I enjoyed the 400-level "Statistics and Probability I" course immensely that I had to take, making me re-think my decision of area of study in graduate school.

I focused mainly on my undergraduate courses along with becoming a course assistant (i.e. like a TA) for a Computer Architecture course for three semesters. I did not do any research or work closely with a professor in a related field while obtaining my degree, something I strongly wish I had done. Although, I have done two computer science-related internships in my final two summers as an undergraduate.

On top of this, my cumulative GPA feels incredibly mediocre at just a 3.34.

I am left with thinking of what the best possible path from here is, in the hopes of obtaining a Masters in Statistics. I have a few options I am looking at:

1.) Graduate schools across the board require letters of recommendations. Yes, I do have the professor I was a course assistant under, another professor that has gotten to know me well through course work, and internship mentors that have seen my industry intership work. However, I have been in talks with a professor on a PhD candidate board that notes that letters of recs for graduate school should come from professors you have worked closely with (i.e. through research) (he notes no distinction from masters vs. PhD). 

Should I look for a research assistant position at a university institution before applying for graduate school (i.e. spend about a year doing research - spring and fall) in hopes of gaining experience and having a professor get to know me in an academia sense? 

2.) Should I apply to a Post-Baccalaureate program in statistics to demonstrate a better GPA and to find a prospecting professor to do research with? I have the mathematics foundation (e.g. Calc 1, 2, &amp; 3 and linear algebra), however, I obviously do not have a lot of statistics under me (e.g. one course as noted above). 

I am leaning towards #1, however, I see the benefits of #2 too. 

If anyone has any other recommendations, please send them my way. I am a bit nervous about wasting any time any one area, unless it is the right move. I would greatly appreciate feedback!
There is a big difference between a Masters program and a PhD program, and there is also a difference between a Masters program by coursework, and a Masters program by research.  Suitability of programs like these, and their entry requirements, generally depend on the specifics of the program and the entry standards of the university.  Having said this, I will try to give some general guidance on this matter.

Master of Statistics (coursework-based): For a student such as yourself, who has an undergraduate degree in a quantitative area outside of statistics (but with a small amount of statistics in that program), a Masters degree by coursework would be an obvious place to start.  A coursework-based Master of Statistics program is generally a good fit for someone coming over from another quantitative degree.  Indeed, these programs are usually designed for students who did not do an undergraduate degree in statistics, but have enough background in mathematics to be able to learn the subject more rapidly than would occur in an undergraduate degree.  (Student who already have an undergraduate degree in statistics may be able to jump this hurdle and go straight into a PhD program.)

Although it varies by university, entry into a coursework-based Master of Statistics program would not usually require an undergraduate degree in the same field, or any research experience.  It would usually be sufficient to have an undergraduate degree in a quantitative subject where you have done the core maths requirements (calculus, linear algebra, etc.) that would allow you to understand graduate-level statistics courses.  If this is a program of interest to you, my advice would be to make inquiries with the universities that are suitable to you, and find out the entry requirements for their programs.

Master of Statistics (research-based): Research-based programs generally have higher entry expectations than coursework-based programs, so for these programs it might be hard to get in (or to do the work) if you do not have a solid undergraduate education in statistics.  For a student like yourself, the more usual path would be to start in a coursework-based masters program first, and then progress to research once you have done enough courses to give you a good grounding in the subject.  In some masters programs there is a combination of coursework and then research.  The coursework comes first and then the research occurs when you have a solid grounding in the field.

Putting the cart before the horse: I am a bit surprised at your suggestion that you would pursue a research assistant position as a means of trying to get entry to a masters program.  You already have some experience as a research assistant, so what you are lacking is not this experience, but rather, coursework in statistics.  In your situation I would think that you could apply directly for course-work based programs in statistics, and this would then be a lead-in to later research programs.