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https://github.com/xori/gamblers-dice

A terrible idea, now real.
https://github.com/xori/gamblers-dice

dice fallacy gambler-fallacy roll statistics terrible-idea

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A terrible idea, now real.

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# The Gambler's Fallacy Dice



> The term *Gambler's fallacy* refers to a misconception about statistics. [...]

In statistics, a random event has a certain probability of occurring. The

fallacy is that if the event has occurred less frequently in the past, it

will be more frequent in the future.

-[Wikipedia](https://simple.wikipedia.org/wiki/Gambler%27s_fallacy)



Well no longer is this a fallacy my friends, these dice are real! If you roll a

20 sided die, and you haven't seen a 20 in a while it is **statistically more

likely** to show up in the next roll with these dice. And the best part, it's

still *uniformly random* for large sample sets!



obligatory chart

![a stupid chart](./assets/graph.png)



## How to Use



```bash

$ npm install --save gamblers-dice

```



```javascript

const RiggedDie = require('gamblers-dice')

const die = new RiggedDie(20) // for a d20



console.log(die.roll()) // 1 -> 20

console.log(die.roll()) // keep using the same instance

```



### Other Languages



The community has ported this to

[Java (@eukaryote31)](https://github.com/eukaryote31/gamblers-dice), [Elm (@solkaz)](https://github.com/solkaz/elm-gamblers-dice), [Python (@torvaney)](https://github.com/Torvaney/gamblers-dice), and [C# (@MrTarantula)](https://github.com/mrtarantula/gamblers-dice). Check them out

if these are your languages of choice!



## I don't get it



Normally when rolling a 4 sided die, you would have a 25% chance of rolling any

given face, at any time. If you rolled a 4, three times in a row it doesn't make

it any less probable of happening the next time. Further, a 1 is not "more

likely" because "it hasn't been rolled in a while".



This library breaks that standard rule.



| Roll | % of 1 | % of 2 | % of 3 | % of 4 | Actual Roll |

|--- | --- | --- | --- | --- | --- |

| 1 | 25% | 25% | 25% | 25% | 1 (⚀) |



In the above example, we got out our fancy die from its box, and rolled.

Because we are gods, we know the probability of each side being rolled, and see

nothing amiss. Every face has a 25%, and we randomly roll a 1.



| Roll | % of 1 | % of 2 | % of 3 | % of 4 | Actual Roll |

|--- | --- | --- | --- | --- | --- |

| 2 | 14% | 29% | 29% | 29% | 2 (⚁) |

| 3 | 22% | 11% | 33% | 33% | ? |



Whoa, that's different, we are now 11% less likely to roll a 1, and indeed, by

luck, we don't. We instead roll a 2, and when we do, we see the probabilities

shift yet again. Let's roll the die a couple more times.



| Roll | % of 1 | % of 2 | % of 3 | % of 4 | Actual Roll |

|--- | --- | --- | --- | --- | --- |

| 3 | 22% | 11% | 33% | 33% | 3 (⚂) |

| 4 | 30% | 20% | 10% | 40% | 1 (⚀) |

| 5 | 9% | 27% | 18% | 45% | ? |



After four rolls, we've yet to see a 4, it is

[obviously due](https://simple.wikipedia.org/wiki/Gambler%27s_fallacy) and

indeed there is now a 45% chance of rolling a 4. If you were going to do

something rash (like

bet on a 4) now would be the time.



## This is stupid, why did you make this



I made a chatbot that rolled dice, and it was constantly criticized for being

"broken" because four 3's would come up in a row.



These accusations would come up even though they (all being computer science

majors) know it's possible (although unlikely) for these events to happen. [They

just don't trust the black box.](https://xkcd.com/221/)



> “Scientists have calculated that the chances of something so patently absurd

> actually existing are millions to one. But magicians have calculated that

> million-to-one chances crop up nine times out of ten.”

>

> ― Terry Pratchett, Mort