Morgan Stanley Traders Lost $390 Million in One Day in August

[jrlvnv]

Quote from IluvVol:

No worries, I also play poker a lot! ;-)

Well you play poker for whatever reason you play it.... I bend over a table because someone needs to toss those cards at you LOL.

Well the light is shed on me. I can't trade I know that. I told a guy who obvious is better then me at math he is a moron which only turn out the moron was the speaker. So I disabled my trading account and going to go find my "trading" self.

Now I am left with the new trading paradox. That is where someone looks for help in trading but the ones that know don't speak and the ones that speak don't really know in the first place. Guess its time to dust of some books and start cracking at it again.

Was kinda funny today since I spent most of the evening explaining this problem to friends and they thought the same thing I thought in the begining. Then when I told them they are wrong they laughed and called me names. I then explained the 10 cup example and can see the light go off and then being told to go F*** myself and how stupid I was to put this much thought into such a stupid problem. Wish I had smarter friends. Enjoy your night ET

 

[IluvVol]

Quote from Capablanca:

Create a decision tree and use it to solve this problem. That should make things self-explanatory.

Dude, the problem was self-explanatory even without a decision tree would you have really thought about it yourself rather than copying stuff you did not understand in the first way. All your earlier post clearly show you did not have a fxcking clue what you are talking about. All you did is call people names who clearly have a better understanding than you about probabilities.

But hey, there are those who admit being wrong and those who just can't say it but rather twist everything around. You are surely one of the latter. Its ok you think you are better than all others...fortunately life and the markets reward those who are better and not just those who think they are better. Thats all I have to say to you. Good luck.

 

[Pholeuon]

Young boys, do you believe that exactly this one problem was one of those I received in 1975 on something like intelligence test in my country?
Btw, in test were about 20 chess masters and about 3/4 of us replied correctly.
We had just 3 minutes think about every problem so it was not so easy like it looks.
Btw, Bobby Fisher was my idol at that time
Another problem was with 3 white and 2 black hats, with transport of goats through river and man less know.
There are not old jokes just old peoples. I remember we were discussing such problems with same pleasure like you now. Ad do you believe they were no computers at that time? Can you believe that somebody had over 30 years when his fingers first time touched keyboard on PC?

 

[Capablanca]

Quote from IluvVol:

Dude, the problem was self-explanatory even without a decision tree would you have really thought about it yourself rather than copying stuff you did not understand in the first way. All your earlier post clearly show you did not have a fxcking clue what you are talking about. All you did is call people names who clearly have a better understanding than you about probabilities.

But hey, there are those who admit being wrong and those who just can't say it but rather twist everything around. You are surely one of the latter. Its ok you think you are better than all others...fortunately life and the markets reward those who are better and not just those who think they are better. Thats all I have to say to you. Good luck.

There is a way of solving the problem logically without using a decision tree but using a decision tree properly I think requires the 16.666% calculation.

You say I copied someone? Who? You say I called someone names? What did I call them? Get your facts straight. When it comes to twisting everything around you seem a dab hand at it. Guess you are one of those people here who delight in provoking people. I'd rather not participate in your games. I'll leave you to your little sandbox now.

 

[Pholeuon]

Ok, young boys, because it seems that you did not understand the problem fully and you speak about trees and probabiltity and staticstic, overcomplicate it and not use elementar logic I try it explain same way like replied young chessmaster 30 years ago:

You choosed one cup.
Because the owner will always show you empty cup THIS INFORMATION YOU DO NOT NEED.
In fact he is offering by switch to you possibility play guessing 2:1.
With another words, if we will be play guessing, you win dollar when coin is bellow your cup and I win when the coin is in one from my 2 cups will you agree? For sure not! I must with with my 2 cups against your 1 cup in longer run.
But this is option exactly option that switch offers to you!
Showing empty cup is just fooling you, this does not have any importance, it does not bring any additional information. In poker it is caled a bluff.

If the question will be without showing emty cup. Ok, you choosed one cup. Want you switch against my 2 cups? Everybody will say YES!
Simple and straight. You do not need computer and use of statistic.

 

[sprstpd]

Quote from Pholeuon:

Young boys, do you believe that exactly this one problem was one of those I received in 1975 on something like intelligence test in my country?
Btw, in test were about 20 chess masters and about 3/4 of us replied correctly.
We had just 3 minutes think about every problem so it was not so easy like it looks.
Btw, Bobby Fisher was my idol at that time
Another problem was with 3 white and 2 black hats, with transport of goats through river and man less know.
There are not old jokes just old peoples. I remember we were discussing such problems with same pleasure like you now. Ad do you believe they were no computers at that time? Can you believe that somebody had over 30 years when his fingers first time touched keyboard on PC?

You definitely need to join the Old Farts thread.

 

[GTS]

Quote from Capablanca:

Let's see. What is the ratio between 1/6 and 1/3? Same as 1/3 to 2/3. Do you understand why that is pertinent to the given example and the Wikipedia explanation? Probably not.

The fact that the ratio's are the same is not relevent - the answers you gave were wrong and its the answers that matters here, not the ratio's between them.

1/6 written in English is 1 out of 6. To say that a 1 out of 6 chance (~16%) is the same as a 1 out 3 chance (~33%) is incorrect.

The odds that the original cup you pick has the coin is 1 out of 3, 1/3, 33%.

The odds that switching to the remaining cup will yield the coin after an empty cup is revealed is 2 out of 3, 2/3, ~66.6%.



Now look what you wrote and say that it is correct:

Quote from Capablanca:
2/3? How did you come up with this figure? If we are presuming an independent trial between 2 cups then the chances are 1/2. But we have a dependent case. How can the chances be greater than 50%? Are you saying undergoing a previous choosing actually increases the chances? Logically the extra step should decrease the chances. The correct probability in this case is 1/3.

 

[Capablanca]

GTS solve the problem through use of a decision tree properly and you will clearly see where the 16.66% comes in.

That the calculation is relevant is the entire point of my participation in this thread. Batman28's methodology is sound. His conclusions, however, are probably not.

As for the 1/6, 1/3, or 2/3 odds, I think I have made it very clear it depends when you pose the question and what question exactly you pose. If you still cannot understand why our initial answers differ, I'm willing to live with it. Good day.

 

[sjfan]

Quote from Capablanca:

GTS solve the problem through use of a decision tree ...

Stop. I have an advanced degree in a field that makes ample use of game theory and statistics (to establish that I do, in fact, know what I'm talking about). This problem is well settled in both. It's not an opinion answer, but a mathmatical one. The monte hall problem is a simple construction that can be EXPLICITLY solved (yes, using decision tree if need be. but easier if just using bayes' rules).

YOU are the one arguing that 1+1 = 3. YOU show us the decision tree and we will tell you why you are wrong. Not our opinion on why you are wrong, but why in fact you are - this is math, not comparative lit. There's a provably right answer and a wrong answer.

 

[Capablanca]

Fine. I think I already did this but the spacing came out badly. We'll see how it goes this time.

T1 T2


* 1/2 = 1/6 -> 1/6 -> (1/6)/(3/6) = 1/3
1/3
* 1/2 = 1/6 -> N/A

* 1/2 = 1/3 -> N/A
2/3
* 1/2 = 1/3 -> 1/3 -> (1/3)/(3/6) = 2/3

Total
1 1 3/6 1

First part decision tree. Second part reformulation of the question. If you have any problem with the logic go ahead and criticize.

By the way the way of solving this that I prefer is the one given by Pholeuon.

[Tried to edit the spacing as mentioned to make it clearer but cannot get it to align properly.]