Why do I see "Trends" in Randomly Generated Data?

Quote from Rahula:

I've created an excel file I call "random chart generator". The weird thing is that most of these charts look exactly like market charts and you can apply all kinds of TA tools like moving averages, and trendlines to these charts.

If you don't believe me, see for yourself. Type in =RAND()*(-1-1)+1 into excel in column A. Then create a rolling sum of column A in column B. Then create a chart based on column B values and add a moving average.

Now what to make of this? I suppose when most people see a 7,7,7,7,7,7 result in the lottery they see a 'trend' even though it is just as random as 23,42,11,14,33,8 lottery result - both events have an equal probability of happening.

Now if the markets are random and the market closed up,up,up,up,up,up,up,up,up,up,up,up 12 days in a row - most people would likely be talking about it as a n-sigma event or a "black swan" even though it is just as unique and random an outcome as a up, up, down, up, down, down, down, up, down, up, down, down 12 day series of closes.

Now doesn't a random market assumption mean that both mean reversion and trend trading strategies don't have any science to back it up and at the end of the day it all comes down to luck?

I know, scary thread.


your initial assumption is that markets are a random walk ..
which is clearly wrong. people react to market conditions, most decisions are not made by a roll of a dice
 
Quote from neophyte321:

your initial assumption is that markets are a random walk ..
which is clearly wrong. people react to market conditions, most decisions are not made by a roll of a dice

i don't feel that the roll of the dice or spin of the wheel is random either.

mb
 
Quote from MarkBrown:

i don't feel that the roll of the dice or spin of the wheel is random either.

mb


well, perhaps you do a little test, roll a die 10,000 times and provide us the results.


We might agree on this ............. there have been times when -I KNEW WITH ZERO UNCERTAINTITY what the die would land on ...

and it landed on that number, defying all explanation


the fact is, there is magic, ... let science be damned
 
Quote from neophyte321:

http://random.org


does the best at explaining this ... in my opinion


also i believe that there is nothing that is random, i feel there are only choices which effect outcome. even events which occur can be traced to choices which were made that infect the outcome.

yes i meant to use the word "infect" because that is the apparent view from the unenlightened of this subject.

mb

random is a word for the ignorant to explain away what they can't comprehend. copyright 2008 mark brown
 
Quote from MarkBrown:

also i believe that there is nothing that is random, i feel there are only choices which effect outcome. even events which occur can be traced to choices which were made that infect the outcome.

yes i meant to use the word "infect" because that is the apparent view from the unenlightened of this subject.

mb

random is a word for the ignorant to explain away what they can't comprehend. copyright 2008 mark brown

so your a determinist ... yawn.

when the day arrives that every input parameter can be calculated in adance, I'll go on saying a dice roll is random. It's so much easier and far less pretenious than explaining the "enlightened" opinion....
 
in rahulas second post on page 1 where he puts up a bunch of psyche test quotes ,BIAS is mentioned several times, then sprinkled thruout all these replies,yet evryone is concentrating on systems to figure out the mrkt. Cnbc,wall street, upgrades and downgrades on stocks and funds, all these plant a BIAS in the publics mind, and people invest accordingly,right now they are telling us the sky is falling, and if you read the daily thrds where people are posting thier pre mrkt opinions, everyone thinks the way the media has conditioned us,doom,doom, doom. I know things have changed with electronic trading but the gyst is still the same,watch the BIAS in the mrkt and u will see strength and weakness,overbought and oversold . I see this whole sky is falling mantra getting tired, i see Ben reluctant for another rate cut,rule out a .75,wouldn't bet on .50, maybe one more week of selling or even a bounce sometime this week... i have no data to back this up, only BIAS , to much data and u can't see the forest thru the trees
 
Quote from MarkBrown:

also i believe that there is nothing that is random, i feel there are only choices which effect outcome. even events which occur can be traced to choices which were made that infect the outcome.

yes i meant to use the word "infect" because that is the apparent view from the unenlightened of this subject.

mb

random is a word for the ignorant to explain away what they can't comprehend. copyright 2008 mark brown

I would agree, adding that any technology sufficiently advanced appears as magic or as impossibility to those who lack an understanding of it. Einstein made this point around the time traditional physicists were scoffing at his new and unproven theories.

Perhaps this debate on are market randomness has a similar division. Some take a definition of random and attempt to find ways that the market matches that definition and assume this proves something about the market. It only proves that given enough motivation one can find arguments to support any proposition in most domains.

Take the argument over say the surge in Iraq. Are large bombings down? - Yes. So is it the solution for that mess? If you just count bombings you have to say yes. Are the forces that control the Iraq government using it to build a stable government that addresses the religious divisions that are hundreds of years old?...No. So short of keeping US forces there for 100 or 500 years to suppress the civil war, will the surge bring peace and democracy? Unknown, but I wouldn't invest in it.

A suggestion: for a moment let’s abandon theoretical arguments on what the market is.

Instead will those who advocate a random nature state a practical measure which if exceeded would cause them to question their position? Those with a non-random perspective can do the same.

Random guys might say:

A Profit Factor greater than X for at least Y trades over Z bars would call into question the random theory.

Non-Random guys can counter:

Fine, here is an approach that exceeds those numbers.

Thus we go from theoretical debate to a "boots on the ground" actuality.

Jerry030
 
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