Questions tagged [statistics]

Statistics deals with the mathematics of probability-based games. This tag should be used for questions about tabletop game mathematics that relate to mechanics rather than game elements such as skills or attributes, and have relevance to RPGs in particular.

This tag should be used for questions that:

  • Are about tabletop game mathematics.
  • Relate to mechanics rather than game elements such as skills or attributes.
  • Have relevance to roleplaying gaming.

Statistics attempts to ask, "If I do this X times, how many times will I get the desired result?"

In games powered by a random outcome mechanic such as dice or cards, statistics is used to get a better understanding of how mechanics were designed to work and how they can be used in play.

Sites like AnyDice provide opportunities for a more in-depth exploration of probability on a per-case basis, while the Wikipedia article on probability is another good resource for those who would like to learn more about the subject.

Note that this tag should not be used for questions about record-keeping. Also, sometimes attributes of a character (such as ability scores) may be called "statistics", but keep in mind that such a meaning does not fall under the scope of this tag. (See also: and .)

383 questions
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What is the chance of rolling at least 10 before a 1 on a d20?

I need at least a 10 on a d20. I can roll until I get it, or I get a 1. What is the chance I succeed? I would like to have the general formula, not just for 10. The chance of success on the first try is 55% (11/20). If I do not succeed, which has a…
András
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How do I mathematically find this distribution?

I roll 10d6. I can then reroll any ones or twos. Then, I can reroll any ones. What is the distribution of the number of sixes I will have?
7
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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 classes as well as options between classes to…
Joshua Aslan Smith
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How can I determine the rolling curve of this roll under system?

The system The system relies on Traits and Skills (which both range from 0 to 6). Players rolls a number of d6 equal to the Skill they're using. Any die result equal or under the related Trait value is considered a success. Example: Bob attacks…
ssavinel
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Help Needed With Probability Math for 2d10

In my Old School D&D campaign, I instituted a house rule to help the PCs raise their ability scores. Each ability score has a "fractional ability score". This is a percentile rating that starts at 0% at first level. Every time a PC levels up, they…
Discord
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How to calculate Yahtzee-like probability without too much by-hand work

So I'm working on a game that's got (to my knowledge) a novel mechanic; at least as far as tabletop roleplaying goes. So the central game mechanic is essentially lifted from Yahtzee: characters want X of a kind or a straight of X dice in a row, but…
Kyle Willey
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What would the distribution curve of a 2d6 + card(s) look like?

I'm developing a new RPG and was wanting to use things readily available in most homes so as not to create a burden to play. The solution I came up with was 2d6, which the max is 12, and a deck of cards which Aces = 2, and kings & jokers (if used) =…
Jesse Cohoon
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Producing a similar distribution to 4d6k3 but for the range [-4, 4]

I'm making a fork of D&D 5e (based on the SRD but then customized) and one of the changes I'm making is removing the whole score/modifier distinction and just going with a simple "score == modifier" model. That is, ability scores are all in the…
Benjamin T Hall
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Help With Trophy Dark and Trophy Dark Risk Roll Probabilities

Has anyone done some basic probabilities on the Risk Roll from Trophy Dark or Trophy Gold? This level of statistics is well beyond my knowledge. Risk Roll A player will build two D6 dice pools. One pool will be "light" dice and the other pool will…
Steve
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Dice probability in variable pools with receding difficulty

Can't quite wrap my head around how to go about this (outside of brute forcing it with manual calculations, which isn't ideal given variable difficulties and variable numbers of dice) so I figured I'd ask here. I'm playing in a game where I can…
John
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