Tau Empire Codex 2013 | Army Builder Program
Dark Angels Codex 2013
Chaos Daemons Codex 2013
Chaos Space Marines Codex 2012

Warhammer 40k Forum Tau Online

 

Warhammer 40K Forum

Do you believe me...?
View Poll Results: See Thread.
0cm 15 35.71%
10cm 17 40.48%
20cm 3 7.14%
30cm 2 4.76%
50cm 2 4.76%
99cm 3 7.14%
Voters: 42. You may not vote on this poll

Reply
Old 08 Mar 2010, 16:51   #1 (permalink)
Shas'O
 
Join Date: Aug 2006
Location: Is the Politiburo smoking weed?
Posts: 5,144
Default Do you believe me...?

If you take a coin and a counter, and say that every time it comes up heads, I will move my counter 1cm to the left, and every time the coin comes up tails 1cm to the right.

What is the most likely distance to find my counter from where it started after 100 coin flips?


Vote Now!

[hr]

This thread came into my head because in another thread somebody mentioned that guy who flipped a coin for a year, and it reminded me of this interesting fact.

Don't read the spoiler until you have voted.

[spoiler]
The actual answer will supprise you;

It's 10cm.

If you don't believe me go try it out yourself, if you don't have the time for a hundred coin flips, there are enough random number generators out their to give you your data set, or alternatively use excel or some other spreadsheet program.

So why is that?
Well at first you might think that the odds of going right or left are 50:50, thus you are just going to move back and forth about the starting position.

While it is true that the odds are 50:50, that doesn't imply that you move about the starting position. For instance, take this scenario;

Heads
1cm left

My starting position now is at 1cm left.

Say I flip 4 more times, then the possible outcomes become the following list;



As you can see there is a strong likelihood that the order of the flips will not generate a perfect 50:50 split. Thus after any finite number of flips, you will indeed have a finite probability of being some distance away from your starting point.

Interesting eh?

Play it on your friends (but make a bet first ).
[/spoiler]

Gen
Genmotty is offline   Reply With Quote
Old 08 Mar 2010, 16:55   #2 (permalink)
Shas'O
 
Join Date: Jun 2009
Location: That bitter taste in the back of your throat, the one kinda wrapped around your uvula that is all that's left of your Pride.
Posts: 5,841
Default Re: Do you believe me...?

Hmmm, interesting i picked 10cm for reasons im not saying incase it sways the vote.

And to prevent my own headdesking and dreadsocking from Gen.:P
__________________
Quote:
Originally Posted by Circus
It is (and this is an objective statement, looking at examples over the last century) really ****ing hard to terrorise the British.
Quote:
Originally Posted by Shas'o Ahab
In parting, I've discovered why Farsight started his breakaway faction...
*Farsight looks at Dawn Blade* "Shiny..."*Farsight picks up Dawn Blade and looks around* "... let's be bad guys."
Quote:
Originally Posted by The man they call Waffles
Jayne you y'xa'uuk legend
The Man They Call Jayne is offline   Reply With Quote
Old 08 Mar 2010, 17:40   #3 (permalink)
Shas'Vre
 
Join Date: Dec 2007
Location: United States
Posts: 1,106
Default Re: Do you believe me...?

Your poll options seem to indicate absolutes, rather than a range of possibilities. So despite my vote (which turned out to be correct), I'm going to have to answer your question of "Do you believe me?" with a hearty no, no I do not.

When I get the time, I'll perform the 100 coin flips and see if I come up with a number not on your list of options.
__________________
IcyCool is offline   Reply With Quote
Old 08 Mar 2010, 17:52   #4 (permalink)
Shas'El
 
Join Date: Dec 2004
Location: In my secret lair plotting forum domination....hehe
Posts: 3,804
Send a message via MSN to Tau-killer
Default Re: Do you believe me...?

[spoiler]Hmm, as a mathematician I have to object to the rather sloppy and vague way you've asked the question, Genmotty - which is strange since you're usually the one calling others out for this! The correct answer to the actual question asked: How far will my counter be from where it started after 100 coin flips? is:

The counter will be at a distance 2n from where it started where n is an integer belonging to the set: {0, 1, ..., 50}

Having said that, I will stop being pedantic and acknowledge that it is clear that the question you meant to ask was: 'At what distance from the starting point is the counter most likely to be after 100 flips.'

Obviously, the answer to this question depends on whether the question literally means distance or whether it means the vector alternative - displacement. Most people would intuitively think that the answer to this question is 0 - because they automatically think in terms of displacement. And in terms of displacement, they're absolutely right. Thinking in these terms, the point 2 centimetres to the right of the starting point (for example) is considered distinct from the point 2 centimetres to the left of the starting point. However, when strictly considering distance, these points are effectively no longer distinct, so their respective probabilities are combined. Thus it should not be surprising at all that the probability that the coin moves 0 distance is no longer the most likely outcome. I shall take your word for it that 10 cm is indeed the most likely outcome.[/spoiler]
__________________
I never bluff, TK.
Tau-killer is offline   Reply With Quote
Old 08 Mar 2010, 19:13   #5 (permalink)
Shas'Vre
 
Join Date: Jun 2008
Location: London/Birmingham
Posts: 1,804
Send a message via MSN to coolmule
Default Re: Do you believe me...?

I went for 10, but I really wanted to pick a number between 0cm and 10cm.
__________________
coolmule is offline   Reply With Quote
Old 08 Mar 2010, 22:35   #6 (permalink)
Shas'O
 
Join Date: Aug 2006
Location: Is the Politiburo smoking weed?
Posts: 5,144
Default Re: Do you believe me...?

True TK, I was being sloppy, but then it was more a bit of fun then something serious.

I'll edit it a bit.

Gen
Genmotty is offline   Reply With Quote
Old 08 Mar 2010, 22:36   #7 (permalink)
Shas'El
 
Join Date: Jan 2005
Location: Wouldn't you like to know... pervert
Posts: 4,077
Default Re: Do you believe me...?

This is in no way fun :P
__________________
If you're new here and you have a problem, don't be afraid to PM me and ask about it. I'll try to help you in any way I can
Quote:
Originally Posted by Kaffl
That's what the new Space Marine codex relates to. Grilled puppies.

Thanks to JD for the awesome siggy
Tim the Tau is offline   Reply With Quote
Old 08 Mar 2010, 22:45   #8 (permalink)
Shas'Vre
 
Join Date: Jun 2008
Location: London/Birmingham
Posts: 1,804
Send a message via MSN to coolmule
Default Re: Do you believe me...?

Quote:
Originally Posted by The Laughing Man
This is in no way fun :P
Agreed lol
__________________
coolmule is offline   Reply With Quote
Old 09 Mar 2010, 00:03   #9 (permalink)
Shas'Vre
 
Join Date: Nov 2006
Location: UK
Posts: 1,614
Default Re: Do you believe me...?

Im the real world perhappppps...
Still, since the more repetitions there are, the closer to the expected average an outcome will be (im suure therees some name for this shizz...its been a few years since i did alevel maths statistics ) .

Id support the theroy that if you flipped said coin 10,000,000 times you would still be within 10 cm of your start point at the end of those flips
Duno ifi making sense, maybe ill explain tomorrow.
If im not then atlest ive learnt one thing today, never try to read and reply to one of Gen's topics whilst drunk.
Thantos is offline   Reply With Quote
Old 09 Mar 2010, 16:52   #10 (permalink)
Shas'O
 
Join Date: Aug 2006
Location: Is the Politiburo smoking weed?
Posts: 5,144
Default Re: Do you believe me...?

Quote:
Id support the theroy that if you flipped said coin 10,000,000 times you would still be within 10 cm of your start point at the end of those flips
Nope you would be 3,162cm from your start point...

Gen
Genmotty is offline   Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On