Can anyone explain a Dirichlet distribution?

Question

Please in ENGLISH tell me what it is and more importantly why I should care. Can you give a quantitative example of when they woudl be used.

Please to do not cut and paste from Wikipedia. I consider that an excelent example of what an answer that is NOT in english looks like.

Perhaps my flipant phrasing of the question invited more flipant responses than I desired like the following:

"I'm guessing the reason you should care is because knowing the answer will help you get a good grade in class."

Actually, I've been done with classes (at least as a student) for some time now. The reason I do care is that I'm considering applying expectation-maximization to some data I'm analyzing and the reference I was reading on EM gave an example with a Dirichlet distribution. By "why should I care" I really meant where do they come up and how does one (through what math) derive it from the underlying process giving rise to the distribution.

Answer 1

try this site, it might help you


http://www.cis.hut.fi/ahonkela/dippa/node95.html

Answer 2

The site jamaica referenced can tell you what a Dirichlet distribution is, but why you should care is a question only you can answer. I'm guessing the reason you should care is because knowing the answer will help you get a good grade in class.