Quote from Whisky:
I believe Martingale does not work in a random normal distribution, and is lethal in a fat-tailed distribution (like the markets).
. That said, I know exactly who is on the other side of my trades and why. Quote from crash n burn:
i have studied extensively market occurrences and there are certain events that happen fewer times than a normal distribution would predict and certainly much less than a fat tail would suggest.
for instance, number of days the market goes down 5 times in a row is about half of what the normal distribution would suggest (based on 100 years of DJI historical records)
i have pinpointed this in my earlier post alluding to the fact that market occurrences are strictly dependent from each other while in the flip of a coin they are not. this is one of the most interesting aspects of market behavior and probably one you should study thoroughly.
Quote from Mike805:
Whisky,
It seems you've touched a nerve with some posters here. I'll go ahead and pinch that nerve.
"Fooled by Randomness" is not only a good book but the term is perhaps nowhere as readily apparent as it is in this forum. It is somewhat satisfying to know how many completely clueless people think that they understand a market dynamic, let alone the foundation of a true edge. Let them trade, the more the merrier I say. That said, I know exactly who is on the other side of my trades and why.
My earlier system result posting was meant to demonstrate how easy it is to create a percieved edge. In fact, if you open the attachement below you'll find another manifestation of this random process at work. All I've done is introduced a couple serial dependencies and trivial ones at that. The "results" are neat, eh?
Some poster from 2003 who shall remain nameless mentioned that this exercise proves nothing. Frankly, I'm suprised he's still around trading... understanding randomness is way more important than attaining an edge. In fact, if one doesn't understand randomness to the point of being able to understand the attached results, then, one will never attain a real edge.
Mike
To everyone else here: would you trade this system if you saw only the results report? Be honest.
Quote from wutang:
Correct me if I'm wrong (I'm a noob trying to educate himself on stats and probability) but is this just an example of data snooping?
Quote from Whisky:
Since each win or loss has a 50% chance of going the other way, by definition, regardless of SIZE, the aggregate does too by commutative properties of the addition. Of course, you must substract slippage and commissions each day. Of course you could have made the proof yourself had you thought about it for a few minutes, hours, days, weeks or years.
http://en.wikipedia.org/wiki/Commutativity
So, as you can prove to yourself and others, what you think matters, does not matter at all in reality.
Now...if you replace the coin tosser for a "more intelligent" algo. Then yes, size of wins and losses as well as the %W and %L come into play.