Switch Theme:

Bad dice rolls how do you see them  [RSS] Share on facebook Share on Twitter Submit to Reddit
»
Author Message
Advert


Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you:
  • No adverts like this in the forums anymore.
  • Times and dates in your local timezone.
  • Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance.
  • Email notifications for threads you want to watch closely.
  • Being a part of the oldest wargaming community on the net.
If you are already a member then feel free to login now.




Made in us
Longtime Dakkanaut






Louisville, KY

Grakmar wrote:
SaintHazard wrote:
His grasp of probability is so horribly bad that I'm simply ignoring his post. What you're suggesting happened is entirely possible, and more probable than he makes it sound.

He might actually be an idiot. I'm not certain.


What am I calculating wrong?

The probability of a miss on one shot is 1/3, two misses on two shots (1/3)^2, three misses on three shots (1/3)^3. So, the probability of missing all of the first 21 shots is (1/3)^21. The dice are then all re-rolled and the probability of all those re-rolls missing is (1/3)^21. The probability of both those events happening is (1/3)^21*(1/3)^21 = (1/3)^42 = 1/(1.1*10^20).

Where's my error?

No, your actual calculations are correct. If he were to roll 42 dice in a row, there's a (1/3)^42 chance of rolling a 1 or a 2 42 times in a row.

The second part of your analysis is in question.

A lot of people misinterpret probability as a flat "it will take x years to get y result if you constantly do z"

It won't take him trillions of years to get that result. There is a (1/3)^42 chance that he'll get it next time he rolls 42 dice.

What you've assumed is that he has to roll 42 dice that many times and the last result will be the one he's looking for... however, it could just as easily be the first result. The second part of your analysis simply is not how probability works.

DQ:80+S+++G++M+B+I+Pw40k10#+D++A++/areWD-R+++T(D)DM+ 
   
Made in us
Fixture of Dakka





Chicago

SaintHazard wrote:
No, your actual calculations are correct. If he were to roll 42 dice in a row, there's a (1/3)^42 chance of rolling a 1 or a 2 42 times in a row.

The second part of your analysis is in question.

A lot of people misinterpret probability as a flat "it will take x years to get y result if you constantly do z"

It won't take him trillions of years to get that result. There is a (1/3)^42 chance that he'll get it next time he rolls 42 dice.

What you've assumed is that he has to roll 42 dice that many times and the last result will be the one he's looking for... however, it could just as easily be the first result. The second part of your analysis simply is not how probability works.


Ah, true enough. I perhaps got a little "overzealous" in that description.

But, I do think those odds are low enough that you couldn't reasonably expect to see those results on fair dice. If you did, it's much more likely something is messing with your true probability than to say it was an actual legit roll.

6000pts

DS:80S++G++M-B-I+Pw40k98-D++A++/areWD-R+T(D)DM+

What do Humans know of our pain? We have sung songs of lament since before your ancestors crawled on their bellies from the sea.

Join the fight against the zombie horde! 
   
Made in us
Longtime Dakkanaut





here is my question for all of you that only use dice that roll high, how often do you fail LD.
   
Made in us
Aspirant Tech-Adept





St. Louis

"Bad Luck" with dice is not really what people make it out to be. People tend to over exaggerate their bad rolls, and not take as much notice of their good rolls. Even in a game where you think you rolled horrible you probably rolled average. You see the ones and twos and remember them vividly. The 5's and 6's you see and move on.

People tend to lean towards the bad and dramatic and remember it better. The same reason the news is depressing, it leaves a lasting impression.

You may miss rolls in tight spots, but overall I would think most people roll the same from game to game, you just remember the bad dice more. Take a poll on the next gaming night at your store. I know in mine, at least 50% of the games people complain that they rolled well below average.
   
Made in us
Decrepit Dakkanaut





Vallejo, CA

Smarteye wrote:Call me supersticious, but before I start a game I roll all my dice. Any that roll 4+ I use for the game and the rest I put back in the cube. If that's not neurotic enough, if anyone else touches a dice I isolate it from the others for at least a day.. lol

I'm guilty of somewhat similar things myself. Before I make a big roll I'll roll some dice on the side of the table. If I'm looking for a leadership test I'll pick up ones that just rolled high, and if I want to pass some armor saves I'll pick up ones that turned up 1's and 2's. That and I will often use different dice to roll to wound then the ones that I just used to hit.

I know it doesn't help, but...

Melchiour wrote:"Bad Luck" with dice is not really what people make it out to be. People tend to over exaggerate their bad rolls, and not take as much notice of their good rolls. Even in a game where you think you rolled horrible you probably rolled average. You see the ones and twos and remember them vividly. The 5's and 6's you see and move on.

People tend to lean towards the bad and dramatic and remember it better. The same reason the news is depressing, it leaves a lasting impression.

Right. That and I think people are quick to overestimate their odds in the first place, making bad luck seem worse and regular luck seem bad. Yeah, a dark lance is a good weapon, but just shooting one at a tank is actually unlikely to produce the desired result (I mean, even a 3x DL ravager only causes about .75 penetrating hits per volley against AV14, and that's assuming no cover, etc.), when it fails to horribly mangle the tank in a single go, that's actually much closer to what's most likely to happen than most people realise, rather than just more bad luck.

Melchiour wrote:You may miss rolls in tight spots, but overall I would think most people roll the same from game to game, you just remember the bad dice more. Take a poll on the next gaming night at your store. I know in mine, at least 50% of the games people complain that they rolled well below average.

This is true. That's why I write battle reports. My worse than average luck is actually documented.


Your one-stop website for batreps, articles, and assorted goodies about the men of Folera: Foleran First Imperial Archives. Read Dakka's favorite narrative battle report series The Hand of the King. Also, check out my commission work, and my terrain.

Abstract Principles of 40k: Why game imbalance and list tailoring is good, and why tournaments are an absurd farce.

Read "The Geomides Affair", now on sale! No bolter porn. Not another inquisitor story. A book written by a dakkanought for dakkanoughts!
 
   
Made in us
Grisly Ghost Ark Driver






Myself I believe it comes down to your army when you roll your dice, whether they feel like killing things or just sitting around in orbit drinking tea by the teleporter. The other day did a 2500 game vs Blood Angels with the 'crons and my dice were on fire, all his transports wrecked/exploded by turn 2 and rolling WBB's like crazy. I'd chalk it up to my army telling me to not shelve it anymore as they can prove themselves, that or my Necron Lord was pissed since Dante NEVER called back after the Gehenna Campaign.
   
Made in se
Fighter Ace





Sweden

...

It's dice, they are supposed to be random, and even if they roll six ones in a roll, it's random.

Bottom line, we are mostly playing games that are totally random. The sooner we all realize that, the less rage they will induce. Dice are people too, but they are twisted, wicked, sadistic mother-truckers who we should have exterminated back when Caesar said "Alea jacta est"...

Sorry, I blacked out, what were we talking about again?

I won't bother. 
   
Made in us
Longtime Dakkanaut






Louisville, KY

Vargtass wrote:...

It's dice, they are supposed to be random, and even if they roll six ones in a roll, it's random.

Bottom line, we are mostly playing games that are totally random. The sooner we all realize that, the less rage they will induce. Dice are people too, but they are twisted, wicked, sadistic mother-truckers who we should have exterminated back when Caesar said "Alea jacta est"...

Sorry, I blacked out, what were we talking about again?

Except that they're not random.

DQ:80+S+++G++M+B+I+Pw40k10#+D++A++/areWD-R+++T(D)DM+ 
   
Made in gb
Hurr! Ogryn Bone 'Ead!




always pick up the dice that has just rolled a one for when you want to role high or a 6 for when you want to role low

i always put my dice back into my tray the same way round as they just landed so i can keep working through them in that way

mind you it still doesn't always work but theres nothing wrong with a bit of a ritual


Chibi Bodge-Battle wrote:
Bedtime Horlicks malty drink: ON
Comfy Slippers: ON
and relax...
Only Slightly Crazy wrote: GO CROGGY GO!
Underhand wrote:
The answer is never the Devildog.




 
   
Made in us
Longtime Dakkanaut






Louisville, KY

croggy wrote:always pick up the dice that has just rolled a one for when you want to role high or a 6 for when you want to role low

i always put my dice back into my tray the same way round as they just landed so i can keep working through them in that way

mind you it still doesn't always work but theres nothing wrong with a bit of a ritual


As long as you're aware that that's not how probability works... if the die just rolled a 1, it's not "more likely" to roll a 6, or anything but a 1. It had a 1/6 chance to roll a 1 the first time you rolled it, and it has a 1/6 chance to roll a 1 the next time you roll it.

But like you said, nothing wrong with a ritual that, if nothing else, makes you more confident and feel a bit better about your rolls.

DQ:80+S+++G++M+B+I+Pw40k10#+D++A++/areWD-R+++T(D)DM+ 
   
Made in us
Decrepit Dakkanaut





Vallejo, CA

right, your odds of any particular die coming up any particular roll are always the same, but the odds of the die rolling the same number twice aren't as good as it rolling two different numbers.

There was someone I once played with who always arranged his dice so that they sat in the cube with the 6 side up. His theory was that the slow, gradual process of plastic deformation would cause gravity to eventually weight his dice for him.

Your one-stop website for batreps, articles, and assorted goodies about the men of Folera: Foleran First Imperial Archives. Read Dakka's favorite narrative battle report series The Hand of the King. Also, check out my commission work, and my terrain.

Abstract Principles of 40k: Why game imbalance and list tailoring is good, and why tournaments are an absurd farce.

Read "The Geomides Affair", now on sale! No bolter porn. Not another inquisitor story. A book written by a dakkanought for dakkanoughts!
 
   
Made in us
Longtime Dakkanaut






Louisville, KY

Ailaros wrote:right, your odds of any particular die coming up any particular roll are always the same, but the odds of the die rolling the same number twice aren't as good as it rolling two different numbers.

There was someone I once played with who always arranged his dice so that they sat in the cube with the 6 side up. His theory was that the slow, gradual process of plastic deformation would cause gravity to eventually weight his dice for him.

Common logical fallacy. A die that rolls a 1, then is rerolled, has exactly the same chances of rolling a 1 as it did last time. You're making the same mistake Grakmar did, in that you're applying probabilities to a span of time. That's not how probability works. The probability of rolling a certain number applies to that roll and that roll only. It's a one-shot thing, not a thing that happens over time. This is a common mistake, and one I used to make myself.

Now, if you want to apply a span of time, you can, but look at it this way: the probability of rolling a die ten times and getting the same result every time is EXACTLY THE SAME as rolling ten different dice and getting the same result. So, while your logic is partially sound, you're wrong in that rolling the SAME die has absolutely nothing to do with it. I guess that's the point I'm trying to make.

As for your friend, he's technically right, but it'd take a LONG time for that to happen. Hundreds of years, if he wants it to make a difference. But the theory, otherwise, is sound!

This message was edited 1 time. Last update was at 2010/09/16 00:59:57


DQ:80+S+++G++M+B+I+Pw40k10#+D++A++/areWD-R+++T(D)DM+ 
   
Made in ca
Bounding Assault Marine






BC Bud

always pick up the dice that has just rolled a one for when you want to role high or a 6 for when you want to role low

i always put my dice back into my tray the same way round as they just landed so i can keep working through them in that way


I think most people do that. You failed me dice back in the box.

http://www.dakkadakka.com/dakkaforum/posts/list/318353.page My current army list with pics!

2.5k 1.5k 
   
Made in us
Decrepit Dakkanaut





Vallejo, CA

Technically, both the statement "your odds of any particular die coming up any particular roll are always the same" and "the odds of the die rolling the same number twice aren't as good as it rolling two different numbers" are both correct. Of course, the latter has no bearing on the former for any given roll.

Your one-stop website for batreps, articles, and assorted goodies about the men of Folera: Foleran First Imperial Archives. Read Dakka's favorite narrative battle report series The Hand of the King. Also, check out my commission work, and my terrain.

Abstract Principles of 40k: Why game imbalance and list tailoring is good, and why tournaments are an absurd farce.

Read "The Geomides Affair", now on sale! No bolter porn. Not another inquisitor story. A book written by a dakkanought for dakkanoughts!
 
   
Made in us
Longtime Dakkanaut






Louisville, KY

Ailaros wrote:Technically, both the statement "your odds of any particular die coming up any particular roll are always the same" and "the odds of the die rolling the same number twice aren't as good as it rolling two different numbers" are both correct. Of course, the latter has no bearing on the former for any given roll.

More accurately, the latter has no bearing on which die you're using.

You can roll the same die ten times, and it's statistically identical to rolling ten different dice once.

DQ:80+S+++G++M+B+I+Pw40k10#+D++A++/areWD-R+++T(D)DM+ 
   
Made in ca
Bounding Assault Marine






BC Bud

You can roll the same die ten times, and it's statistically identical to rolling ten different dice once.

Statistically yes. But you need to change dice to punish the one that failed you.

http://www.dakkadakka.com/dakkaforum/posts/list/318353.page My current army list with pics!

2.5k 1.5k 
   
 
Forum Index » 40K General Discussion
Go to: