Arial Black
Adventurer
What are the odds of a 3 or 18 with 3d6?
OK, a bit of a tangent because I was trying to do math in my head last night. I know the odds of rolling a 3 or 18 on 3d6 is 1/216 because the odds of rolling any particular number is 1/6. Since we don't care about sequence these are independent events or 1/6 X 1/6 X 1/6 = 1/216.
Basic math, right? But what if I was curious about the extremes? Odds of a 3 or an 18? Once again, seems simple: (1/6 X 1/6 X 1/6) + (1/6 X 1/6 X 1/6) = 2/216 or 1/108.
So even in a village with 108 adults you're going to have 1 person that is at the normal maximum human potential for a particular stat and one at the absolute minimum.
But why stop there? There are 6 ability scores, so the odds of getting a 3 or 18 in one of those ability scores should be 6/108 or 1/18. Which means that in any random group of 18 people you will have (ignoring people that have multiple 18s or 3s) 1 person that as the min and max for every ability score.
What's wrong with my math? Or is rolling 3d6 for ability scores even more unrealistic than I thought?
You're doing it the wrong way round.
It's not that 'in every village of 216 people, 1 is the (joint) strongest man in the world'.
The correct interpretation is simply that in every {statistically average) village of 216 people then one of them will have 18 Str.
It is wrong to conclude that the starting maximum of 18 on 3d6 means that the 'highest stat in the world' is 18. The highest Str score in your world may be 24 for that 20th level barbarian, or 26 if he wants to read that book instead of eat it.
