Self Publishing an Probability math e-book

. . . like there would be two ways to approach the subject: Write a really complex book about probability, or write a simple layman's book about probability.

It seems like you're going for the latter (since you said it would be simple, and you aren't a mathematician by trade!).

In this case, how much information is there really to convey (enough for a book?) I can't think of very many uses for probability that could be generalized for someone who was not familiar with it (and the specific uses--poker, for instance-- have many books about them already.)

Also, how much can someone who doesn't already know about probability be expected to want to learn about it? Forums I read about games which reward players who can handle probability (magic, and axis and allies for example) all have threads where the topic comes up, and then someone explains how it works fairly well. I don't know how much more than that is needed.

That said, it IS a branch of math that is not at all intuitive, and it is one that most people don't know very well at all. It's something I'd certainly love to read more about, but I'd probably want a bigger, heavier book on the subject. Maybe there are enough people in between people like me, and the confused forum goers who cant understand why they didn't draw a land in three cards when their deck is one third land!

That made me kinda think, too. Are there many accessible, fun, math books out there-- Something analogous to grammar's "The Elements of Style?"

I'd actually love to read a short, accessible book about a math subject (like probability) that explained the simple things and why people got them wrong, gave examples, and maybe poked fun at it a little. That said, I'd probably want to read the real book, and not a pdf. I'd feel like I was paying someone for a blog or something.

So there's my opinion: 'Eh, I dunno of that's a very good idea, but it might actually be a really cool idea!'

:)

(Also, you can self publish hard copy books, just like games. Check out superior print on demand. I only know them, because they've linked their card printing services here, before.)

Heck, I'd assert that - in quite a few instances - it's literally counterintuitive. What you expect to be true is incorrect, if not the opposite of what your instinct tells you should be true.

I believe that's one of the reasons people don't understand it well.

You might want to clear that up before writing a book on the subject. :)
If you use a print-on-demand service like cafepress.com I don't see what the harm would be. The most you could lose is your time (which is of value, so don't discount that!) Since there is no inventory, there is no financial risk for you.