Statistics deals with the mathematics of probability-based games.

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99
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How does rolling two dice and taking the highest affect the average outcome?

D&D 5E has an "advantage" concept where instead of rolling 1d20, you roll 2d20 and take the highest. Likewise, disadvantage means rolling 2d20 and taking the lowest. How does this affect the ...
71
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13answers
14k views

3d6 vs a d20: What is the effect of a different probability curve?

What is the effect on game play of replacing d20 rolls with 3d6 rolls in a D&D 4e campaign? I started thinking about this after reading this question where the example was given of playing a d20 ...
40
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7answers
4k views

Is it possible to produce a bowl-shaped probability curve with dice rolls?

In D&D's basic D20 system, you roll one d20 and add in some modifiers, then compare the result to a target number. Each modifier effectively adds or removes a 5% chance of success with the roll. ...
33
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2answers
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What are the statistical implications of doubling damage on crit instead of doubling the dice rolled?

I've been playing with a group that frequently allows players to double the value of dice rolled for crits (and other things) rather than rolling double the dice. Example, someone crits with 2d6 and ...
29
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8answers
16k views

When rolling percentages, do 1d100 and two d10s (percentiles) share the same probabilities?

I know d100s are shunned because they take too much time to roll, and 1d10+1percentile is really fun, but do they share the same probabilities? Is it better to use a (digital) d100? Also, do d100s ...
29
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2answers
2k views

What is the probability of surviving my death saves?

If my character drops to 0HP but is not killed instantly by massive damage, what is the probability that I will stabilize via death saves unassisted/unhindered? As a refresher, here are some of the ...
28
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5answers
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How many rolls does it take to get to six coins?

I'm designing a microRPG and need some help calculating probabilities so I can make an informed decision about how many coins to start with (controlling session duration and early-game frustration). ...
25
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8answers
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What is the statistically superior character creation method, twelve 3d6 or six 4d6?

The D&D 3.5 Player's Handbook gives (among others) two preferred methods to roll ability scores for a new character: a) roll 3d6 twelve times and keep the preferred six results, or b) roll 4d6 and ...
24
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6answers
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Are Earthdawn's dice mechanics as unfair and wonky as my player claims?

After an Earthdawn one-off running Misguided Ambitions with my regular D&D 4E group — because one guy was MIA — I had a discussion with one of the players about Earthdawn's dice mechanics. The ...
21
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4answers
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Is giving one side advantage always equivalent to giving disadvantage to the opponent?

Sometimes, players get advantage; sometimes, monsters get disadvantage. Sometimes it's not clear whether to give someone advantage or his opponent disadvantage, especially in improvised contests (PHB ...
20
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4answers
1k views

Roll For Shoes - Does the advancement system work for longer campaigns?

I'm about to start in on a new campaign with the Roll For Shoes system, but I'm concerned that the characters will swiftly outstrip basic and intermediate challenges as they grow in dice. In the ...
19
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4answers
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How much damage does Great Weapon Fighting add on average?

The Great Weapon Fighting Fighting style states the following: When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two hands, you can ...
16
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8answers
5k views

Can I substitute a d3 with a d6?

I don't have a lot of dice yet, just a basic set of polyhedral dice: 1d4 1d6 1d8 2d10 1d12 1d20 Sometimes an ability or save calls for a die that I don't have. Strike, Unarmed [...] ...
15
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4answers
1k views

Is there a subtle difference between increasing DC and adding detrimental modifiers?

Modifying difficulty works in various ways within and between various roleplaying systems. But generally speaking, it seems added difficulty either modifies the target number (altering the check) or ...
13
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3answers
5k views

What's the probability curve of the D10 Storytelling System?

Recently a friend commented that he thought the dice pool in the d10 Storytelling System actually gave mediocre results, and that by increasing the number of dice thrown you were actually decreasing ...
12
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4answers
325 views

How does replacing Advantage with a flat +2 affect Champion critical hit damage output?

My DM does not like Advantage/Disadvantage. While I disagree with his reasons on this, he has decided to replace it with a +2/-2 rule and I respect him (mostly) enough to follow his rules. I recently ...
11
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4answers
937 views

Chances of rolling up characters for classes in first edition Dungeons and Dragons

I recently read a blog post about the probabilities of rolling up a character that would meet the requirements for all of the different classes in first edition Dungeons and Dragons. I'd love to read ...
11
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6answers
551 views

Are class features, Abilities, and feats that allow −5 to attack to get +10 to damage mathematically sound?

Some class features, abilities of monsters, and feats allow you to take a −5 to your attack roll in order to gain a +10 to your damage roll. At first glance this looks really good, but when will it ...
11
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3answers
440 views

What is the average roll of a die with an expanded explosion threshold as compared to one with an expanded success threshold?

This is going to be a bit of a weird question, but I'm figuring dice pool probabilities for a homebrew system and I want to know how certain abilities should be priced regarding their use. The basic ...
10
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4answers
2k views

What is your chance to win in a contest where you have advantage and your opponent has disadvantage?

I'm trying to think of the answer to a certain problem, but I'm finding it hard to calculate. How much of a statistical edge do you have in a scenario where all of the following are true? You ...
9
votes
3answers
622 views

What is the expected average damage for an area of effect power?

I have spent quite a bit of time coming up with an average damage document for my party and for several other characters. However, the one thing I have not been able to represent well is the average ...
9
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2answers
137 views

How can I get the highest or lowest values of an irregular dice pool in AnyDice?

I want to calculate irregular dice pools, such as (2d10, 1d8) in AnyDice, but I'm having difficulties. What I mean to do is out of a roll of 2d10 and a 1d8, take the highest (or lowest) two values ...
9
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2answers
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How can I model Burning Wheel probabilities in AnyDice?

I have a basic intuition about dice in Burning Wheel, but it's handy to be able to look at actual probability distributions to hone your intuition. Especially since important rolls can involve ...
8
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3answers
2k views

How can I get AnyDice to determine these odds?

After looking at AnyDice's Documentation and Function Library, I remain baffled. I know that AnyDice can do this, but I don't know how to tell it to. Scott Gray's Dice Pool Generator is easier to use ...
8
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1answer
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Average attack bonus of a 30th level character in DnD 4e

What is the average attack of 30th level D&D character? (Of course this number must be calculated without uber-strong homebrew items). My real question is this: What is the average chance of ...
8
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1answer
475 views

How can I simplify a series of rolls without changing probability too heavily?

Ok, I'm working on a combat system converted from a video game to a tabletop game, and I'd appreciate some feedback on how I can make my combat defense system work. Currently attacking is handled as ...
7
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8answers
3k views

How do I approach the probability of a d100, using 2 d100's?

We're running an almost 100% homebrew system, which uses skills in order to craft objects during play. Allow me to first formulate an example to explain my question better: Jack is quite the mason ...
7
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2answers
658 views

How much is a Second roll worth in Modifier Bonus

That is to say, the value of a second roll, how much of a bonus value is it worth. For example: when you make a saving throw, attack or check roll, when does +bonus to the roll and rolling twice ...
7
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3answers
795 views

Considering Complex Dice Roll Probabilities

Hoping someone more math and excel/troll/anydice competent than I can help me out. I've long been considering implementing some Dungeon World style die roll mechanics into D&D. With Next about ...
7
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5answers
400 views

Measuring complexity in 4e characters?

This google doc contains my current work. I am working on a set of quantifiers that can reliably compare complexity between two different characters. At present, I've operationalized 5 factors: ...
7
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1answer
190 views

Are there any guides for using Statistical Analysis for RPG optimization?

I've got a light background in statistical analysis for project management, but I've never applied statistics to analyze RPGs or games for that matter at all. I'm looking to compare options within ...
7
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0answers
809 views

Probabilities using 3d10 as 1d1000 [duplicate]

I'm trying to use anydice to figure out the probabilities of the various values of 1d1000 rolled on 3d10. I want to know stuff like "what's the chance of rolling 900 or higher? How about 950 or ...
6
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2answers
1k views

Polyhedral dice statistics program, spreadsheet, or document

Does anyone know of a program that does statistical analysis on dice rolls, or a document of tables for the same? I am looking mainly for statistics other than d6 (which are very common in most ...
6
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2answers
1k views

Are Half-Elves immune to the paralyzing property of a Ghoul's Claw action?

The Ghoul's Claw attack in the Monster Manual (p.148) has the rider of forcing a save or paralyzing a creature if the target: ... is a creature other than an elf or undead ... My question is ...
6
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4answers
454 views

Can the astrology helping die decrease the chance of success?

Astrology can help most tests, but has a chance of actually taking away a success from the roll, thought it is unlikely. Ignoring the fiction and focusing only on the rules, is there any situation ...
6
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1answer
739 views

Dice pool success probability with one exploding die

I'm looking for the math behind the following: Players have a pool of 3–11 d6s, and have to get from 1–4 successes, "success" being a roll of 5+. One of these dice is special (represented ...
6
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3answers
150 views

Improving “fumbles” when using pools of d10s in TROS

The original rules in TROS use varying pools of d10s to attempt rolling one or more successes against a varying Target Number (e.g., commonly a TN=7). Roll the pool of dice, count up the successes ...
6
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1answer
380 views

Are there statistics of the more played games?

Looking the questions of this site, it seems that D&D, in all its versions and variants, is by far the most played game. But that's not quite true in the people I know, so I think the proportions ...
5
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2answers
249 views

Can you roll a dice pool or multiple dice rolls with only one die?

Say I'm playing Vampire: The Requiem and I need to roll 5 d10's. Can I roll a d10 5 times instead of having 5 d10's? Can I split it up if I must, so if I only had 4 d10's could I roll the 4, then roll ...
5
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2answers
1k views

How do I calculate dice probability in the A Song of Ice and Fire system?

Say I need a net hit of 20 or higher. I get to roll 5d6 base, but I get a bonus dice roll of +3. I only get to keep the 5 highest so I would be rolling "8d6 drop lowest 3 rolls" I want to know what ...
5
votes
3answers
783 views

How do I calculate the chance of hits?

(I do not know if I should post this in math.stackexchange.com, so I try to phrase it in a way that it makes sense for non-roleplayers. Just in case it gets moved) In the latest two editions of ...
5
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1answer
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How to address Damage/Toughness bias in M&M Tradeoffs

The Basic Problem Right, Mutants and Masterminds is a True20 system where everything is resolved via rolling a d20. Attacks are made by rolling a d20 and adding the attack bonus, trying to match or ...
5
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3answers
260 views

How to compare hit % and damage between 1 attack vs 4 attacks with disadvantage?

Quite a few scenarios here, wish my AnyDice fu were up to par—if it's too much, no need to cover all of them, just the most representative, so I can figure out the rest. For the given character ...
4
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2answers
1k views

Explain why Ubiquity doesn't have an asymmetrical bell curve like most dice pool systems?

A post on Pen and Paper Games forum states that the Ubiquity system does not have an asymmetrical bell curve as other dice pool systems typically do (like the D6 system). Where can I find this ...
4
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3answers
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Calculating dice pool probability with limited rerolls

I need a probability calculation script that works with various dice and dice pool sizes, that accounts for a mechanic that allows you to reroll up to X dice that are failures, but ONLY once per die. ...
4
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3answers
261 views

What is the average outcome of this opposed roll resolution mechanic?

Trying to work out the average number of successes for an opposed roll using the following system but can't quite seem to get it to work in Anydice Roll (3d6-5)+Stat+Skill+Modifier 3 6s = crit, ...
4
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2answers
433 views

What is the formula for average damage for an Avenger against an Oath target?

I am creating a spreadsheet to compute average damage for my party. One of the issues that I am having is calculating average damage for the target of our Hybrid Avenger-Assassin's Avenger attacks ...
3
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4answers
1k views

How do I calculate the chance to hit a given AC?

My current level 2 variant Ranger has the Sharpshooter Feat. His hit modifier is normally +7, but with Sharpshooter it's +2 (due to the −5). I am wondering what the % based chance to hit is ...
3
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6answers
331 views

A system that models improved threat range of critical misses?

Have you ever fumbled with a flail? It sucks, especially when you are first learning it. It can happen very often; Sometimes in such a terrible way it far surpasses the risk of swinging a staff, hands ...
3
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3answers
425 views

What's the probability of getting three matching faces in any one roll of four Fudge dice?

I'm having a little difficulty recalling the procedure for calculating probability of dice results. My question is, using 4 Fudge d6 dice, what is the probability of getting three of any result in one ...