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

If these dudes can lose like that, in spite of having the best equipment ...smartest minds....etc ...where is the hope for a peep squeak like me?:mad: :confused:
 
Quote from Capablanca:

Actually everything I wrote is correct.

The perspective is what is misaligned. I'm looking at it in finer detail.

1/6+1/6 = 1/3

1/3+1/3 = 2/3
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Your quote clearly says that you thought the original odds were 1/6 and 1/3 after switching..now after looking at it with "finer detail" you come to the conclusion that its actually 1/3 and 2/3, just as I wrote.

It takes a big man to admit when you are wrong - you are quite small.

I really liked the part where you attempted to chastise me about reading the article when it appears you are the one who didn't bother to read it.

I know, I know - misaligned perspective...whatever
 
Quote from GTS:

Your quote clearly says that you thought the original odds were 1/6 and 1/3 after switching..now after looking at it with "finer detail" you come to the conclusion that its actually 1/3 and 2/3, just as I wrote.

It takes a big man to admit when you are wrong - you are quite small.

I really liked the part where you attempted to chastise me about reading the article when it appears you are the one who didn't bother to read it.

I know, I know - misaligned perspective...whatever
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Oh brother. Wikipedia is a nice resource but it is useful, believe it or not, to have actually studied the topic too. Maybe you'll understand if you ever find yourself in a job interview asking if you can look up answers on the net.
 
Quote from Batman28:

if you had a chance to change your decision, would you stick to the cup you initially selected (i.e. 2)?

I immediately said yes. anyone with my mindframe would also stick to their original choice - I won't write an essay why.

the 'right' answer of course STATISTICALLY, as he stated, is you should swap and change your decision.
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One aspect of the interview that perhaps was overlooked in this whole discussion was whether the subject can tell if the host is deceitful or not. If the host is deceitful and always turn over the cup only when the subject has correctly chosen, then the subject should never change his selection.
I think subconsciously, Batman28, that you perceived the interviewer as deceitful, as 99% of traders usually are, then you came to the right conclusion. :)
Sources of confusion

One reason the Monty Hall problem may be so counterintuitive is that the host is expected to be deceitful (Mueser and Granberg 1999). If the host opens a door only when the player has chosen correctly, then when the host opens a door the player should never opt to switch.
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Quote from Capablanca:

Oh brother. Wikipedia is a nice resource but it is useful, believe it or not, to have actually studied the topic too. Maybe you'll understand if you ever find yourself in a job interview asking if you can look up answers on the net.
More...
Try to make this about me, Wiki, anything but the fact that you didn't know what you were talking about when you posted.

Sorry but your mental diarrhea its right there for all to see:
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.
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this post reminds me of Monty Hall and gang...




Quote from Batman28:

well guess what, I actually happend to interview at Morgan Stanley quant trading team in London back in July with one of their top guys who reports directly to Yazid Sharaiha - their global head of quant trading.. I remember one of the questions that he asked me which I found ridiculous..

this is what he basically presented: imagine 3 cups and under one of them is a coin - and you have to guess under which the coin is sittin under.. assume the cups are numbered 1, 2 and 3.

now let's suppose you choose one of the cups e.g. 2. He then asks given that you choose any of the cups (2 in our example) and he takes one of the remaining cups away (not the one you chose), and if you had a chance to change your decision, would you stick to the cup you initially selected (i.e. 2)?

I immediately said yes. anyone with my mindframe would also stick to their original choice - I won't write an essay why.

the 'right' answer of course STATISTICALLY, as he stated, is you should swap and change your decision. i.e. if you stick with ur decision then 1/3 x 1/2 = 0.16.. but if you switch (implying from the start the coin was under one of the other cups) then 2/3 x 1/2 = 0.33.. i.e. higher probability.

I argued with him that this form of statistical thinking in dealing in the markets is a joke - and he agreed somewhat - but he said if they have a "quantitative/statistical MANDATE for clients" then they have to follow it and stick to it..

I'm not really surprised this is now happened. it made me think how some of these quant groups 'overfit' life with maths and ignore common sense at times.. i remember something one successful trader I met once said - "we use techniques we cannot explain but they seem to work".. just like the successful gamblers before there was statistics.. in other words, anything that can be explained (take statistics) doesn't ACTUALLY WORK.

p.s. don't pm me askin what I do etc no big deal.. it was just a junior graduate job.. and just to add, I searched him on facebook before the interview and he's on it.. just tels you what sort of people are on facebook too these days..
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Quote from GTS:

Try to make this about me, Wiki, anything but the fact that you didn't know what you were talking about when you posted.

Sorry but your mental diarrhea its right there for all to see:
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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.

As for any supposed mental diarrhea on my part I'm sure anyone who has taken basic Statistics can understand the point I was making which is the same reason I could at least understand the rationale behind batman28's answer. That you do not even seem to recognize the method being employed tells me enough about your own qualifications to judge my answers.
 
Quote from Batman28:

well guess what, I actually happend to interview at Morgan Stanley quant trading team in London back in July with one of their top guys who reports directly to Yazid Sharaiha - their global head of quant trading.. I remember one of the questions that he asked me which I found ridiculous..

this is what he basically presented: imagine 3 cups and under one of them is a coin - and you have to guess under which the coin is sittin under.. assume the cups are numbered 1, 2 and 3.

now let's suppose you choose one of the cups e.g. 2. He then asks given that you choose any of the cups (2 in our example) and he takes one of the remaining cups away (not the one you chose), and if you had a chance to change your decision, would you stick to the cup you initially selected (i.e. 2)?

I immediately said yes. anyone with my mindframe would also stick to their original choice - I won't write an essay why.

the 'right' answer of course STATISTICALLY, as he stated, is you should swap and change your decision. i.e. if you stick with ur decision then 1/3 x 1/2 = 0.16.. but if you switch (implying from the start the coin was under one of the other cups) then 2/3 x 1/2 = 0.33.. i.e. higher probability.

I argued with him that this form of statistical thinking in dealing in the markets is a joke - and he agreed somewhat - but he said if they have a "quantitative/statistical MANDATE for clients" then they have to follow it and stick to it..

I'm not really surprised this is now happened. it made me think how some of these quant groups 'overfit' life with maths and ignore common sense at times.. i remember something one successful trader I met once said - "we use techniques we cannot explain but they seem to work".. just like the successful gamblers before there was statistics.. in other words, anything that can be explained (take statistics) doesn't ACTUALLY WORK.

p.s. don't pm me askin what I do etc no big deal.. it was just a junior graduate job.. and just to add, I searched him on facebook before the interview and he's on it.. just tels you what sort of people are on facebook too
.

http://montyhallproblem.com/

problem has been around for over 50 yrs.

correct answer is you should switch.
More...
 
clients gave him money to gamble the markets,and he gets paid for shuffling cards.

that is how useful quant trading is in REALITY




Quote from zdreg:

Quote from Batman28:

well guess what, I actually happend to interview at Morgan Stanley quant trading team in London back in July with one of their top guys who reports directly to Yazid Sharaiha - their global head of quant trading.. I remember one of the questions that he asked me which I found ridiculous..

this is what he basically presented: imagine 3 cups and under one of them is a coin - and you have to guess under which the coin is sittin under.. assume the cups are numbered 1, 2 and 3.

now let's suppose you choose one of the cups e.g. 2. He then asks given that you choose any of the cups (2 in our example) and he takes one of the remaining cups away (not the one you chose), and if you had a chance to change your decision, would you stick to the cup you initially selected (i.e. 2)?

I immediately said yes. anyone with my mindframe would also stick to their original choice - I won't write an essay why.

the 'right' answer of course STATISTICALLY, as he stated, is you should swap and change your decision. i.e. if you stick with ur decision then 1/3 x 1/2 = 0.16.. but if you switch (implying from the start the coin was under one of the other cups) then 2/3 x 1/2 = 0.33.. i.e. higher probability.

I argued with him that this form of statistical thinking in dealing in the markets is a joke - and he agreed somewhat - but he said if they have a "quantitative/statistical MANDATE for clients" then they have to follow it and stick to it..

I'm not really surprised this is now happened. it made me think how some of these quant groups 'overfit' life with maths and ignore common sense at times.. i remember something one successful trader I met once said - "we use techniques we cannot explain but they seem to work".. just like the successful gamblers before there was statistics.. in other words, anything that can be explained (take statistics) doesn't ACTUALLY WORK.

p.s. don't pm me askin what I do etc no big deal.. it was just a junior graduate job.. and just to add, I searched him on facebook before the interview and he's on it.. just tels you what sort of people are on facebook too
.

http://montyhallproblem.com/

problem has been around for over 50 yrs.

correct answer is you should switch.
More...
More...
 
at the end of the day nothing is produced only more money printed by the FED and the card shufflers dealers and brokers get their commission check.



Quote from vectors101:

clients gave him money to gamble the markets,and he gets paid for shuffling cards.

that is how useful quant trading is in REALITY
More...
 
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