Crossposting on mathoverflow (which I know is discouraged)
It would be dramatically off topic on mathoverflow, which is for research problems. Unless you are planning to publish in a mathematically-related journal somewhere, you probably shouldn't post there.
It might instead be on topic on math, however.
Bloating the question with things like "Please help" or "it is really simple" in the heading
Pointless, since it would be almost immediately edited out, and likely annoy several of our frequent contributors, so it's more likely to cost you answers than gain them.
"please help" is utterly redundant since everybody who posts a question wants help, that's why they're posting. It doesn't do anything to make your post a better question for the site -- in fact the opposite.
if it's really so simple, you should answer it. If you don't know the answer you also cannot actually know how simple it is to answer, you only assume it's simple -- but many questions that are easy to ask are impossible to effectively answer. Being told a question is simple is for me a disincentive to answer because it belittles my contribution in answering a question - before I've even started. Why would I put effort into answering a question that you don't think takes any?
Posting in meta about my problem
Well, sure, but the general advice doesn't change much from several posts here about how to improve questions and how to encourage answers. First and foremost you make it the best question you can.
[In spite of initially thinking there was a problem with the question] I now think this question is answerable, but it could be clearer. I had to reread it several times to see where I had misunderstood. [Now I understand it, I suspect it may be a duplicate. If I can't locate one, I will answer it -- assuming nobody beats me to it.]
You should as far as possible make sure you have posted in the one best place for your question. Is this a stats question at all, rather than a mathematics? If so how is it about statistics? (I realize its origin is in work with models, but the question itself seems (if I have it right) to be just about how percentages work. Consider whether you should request migration to math.SE; if you do think it is a stats question you should try to make that aspect of it clearer)