>Thanks for the reply, Yuri. Could you please check this definition for me in those books, because I simply don't have them. I agree, that life may make some corrections in math functions :)
>
>Besides, Andrew quoted the book of Theory of Probabilities... It's not the same, as Financial Statistics, I believe...

As my professor of Probability and Statistics once said, "to make the distinction between the two, keep in mind that probability is a science, and statistic is a method".

Basically, the probability handles the theoretical odds, assuming a model of independent event, whereas the statistics handle existing data. With a sample or population of data sufficiently large, the behavior observed should converge to the probability distribution which describes it the best, and would hence become predictable at the same large scale (but individual cases would still remain unpredictable). Eventually, you get Asimov's Foundation as a WWIBIIWB (what would it be if it would be) extrapolation of laws of probability applied to social sciences.