Thank you, I get it now.
Huh. My assumptions were wrong. This just makes me feel like without more of a math-brain I can't hope to be a good investor. But I guess the point is to save money, and invest it in a reasonable if not stellar way, and that's better than just saying "I'm bad with numbers so I won't bother".
But I guess that's why I read personal finance advice columns, and haunt these discussion groups. So I can benefit from other people who understand this stuff better than I ever will.
