I plan to conduct independent research on different forms of early childhood education. I have a B.A. in Early Childhood Education but no formal education in research methods or statistics. I was hoping to enroll in a statistics class at a community college (I specifically chose this one because the professor is by far the highest rated and helpful in showing us how to actually conduct research) but the waitlist is full and I probably won't get in if I hope for someone to drop the class. Since I'm not working towards a major (currently, though I do eventually plan on doing a Master's in psychology), would it be best to audit instead? I'm not in a rush so I can wait to regularly enroll next year, though I'd prefer to audit now if it won't make a huge difference in terms of how it'll look to have an audit instead of a grade when I eventually apply for Master's programs.
In general, auditing a class provides somewhat close to zero information for anyone considering your application in the future. At the very best, it shows you were interested in the subject even though you would get no credit for it. Its not much different than taking an online course with no grade, studying on your own, or just showing up to a class without being enrolled. At least in the US, auditing doesn't even require you show up to class, much less do any work, thus why it has little signal meaning.
So I would suggest that if you audit the class, do it for some other reason than what people looking at your application will think of it. It is reasonable to try to audit if you want to improve your training, prepare for a more advanced class (or just taking the same class next semester), just want to do it for fun (I personally plan to audit stats classes in the future, but that's because I'm at a point that no one cares what classes I take so its just for my own utility and interest), want to get to know the professor a bit better to see if you'd like to work more with them or take other classes by them, etc.
If programs you are planning to apply to strongly value or require quantitative/statistical training, though, auditing a class generally won't do it. This completely depends on what sort of program you apply to, as some won't really care about stats preparation anyway, while others will demand a lot more than 1 class in stats and research methods/design. Now would be a good time to look ahead at what sort of programs you are applying to, what they say they like to see, and plan your courses accordingly.
I agree with @BiranH. Auditing just shows that you were enthusiastic about a topic. If knowing that topic is important for the selection committee, then the question for them is probably how well do you know the subject. Based on my personal experience, most students auditing classes usually skip a good number of classes and do not do any homework or project. Hence, their learning is not significant compared to enrolled students. Therefore, I suggest auditing a class only if you want to get familiar with the topic or you need the knowledge to do independent research.
PS #1. I have an engineering background, but AFAIK research methods and statistics are important courses in humanities and covered by almost every humanities curriculum. So, I think auditing or enrolling in those courses before your starting your MSc studies is just a plus point. Hence, not being familiar with them should not be a negative point.
PS #2. Personally, I audited about ten courses during the last year of my undergraduate and graduate studies and they helped me a lot later in my research, projects, and teaching. If you are near the end of your graduate studies (probably doing your thesis), I think it's a good idea to audit courses. However, you should not rely on it as a hiring plus. It's a personal investment.