More Math!

I received a few questions regarding Risk-of-ruin & Expectancy. Well, the math is as follows:

Risk-of-Ruin
-------------
{[1-(W-L)]/[1+(W-L)]}power of U

where

W= probability of winning
L= probability of losing
U= number of units of money in trading account

The objective is to get r-o-r = 0%

Expectancy
------------
[probability of winning x (avg win/avg loss)]-[probability of losing x (avg loss/avg loss)]

The objective is to get a positive expectancy number. Obviously the higher, the better.

So, there you go! For more info, go read Dr Van Tharp's books (e.g. Trade Your Way to Financial Freedom).