I "know" how to do this from my engineer studies but it's coming from very far. That site looks very interesting, I'll check it out tomorrow (one of my flaws is I like too much to just write stuff out on paper). Enough study for today, if my poker tourneys end it's party time :P. Btw I watched the courses from the first two weeks of Mathematical Biostatistics today, can recommend this course greatly, it goes very deep into the fundamentals of statistics to give you a thorough understanding. For anyone interested.