I thought it might be interesting to be able to do a direct comparison between the stats in Empire of the Petal Throne and D&D. EPT uses percentile dice for stats but converting that to 3d6 ranges is just a matter of understanding the probabilities involved. Note that you could quibble a point or two with my 3-18 spreads, since Professor Barker uses nice round numbers that don't map exactly to a 3d6 bell curve.
3-9 Weak -1 to-hit
10-11 Average -
12-13 Strong +1 to-hit
14-15 Powerful +1 to-hit and damage
16-18 Superb +2 to-hit and damage
I like that each range band comes with a descriptive label. 'Superb' is kind of an odd choice for max Str though. I would have gone with 'Mighty'.
3-7 Stupid -1 to-hit and damage, cannot parry, cannot use technological devices, cannot use spells greater than 2nd level
8-9 Dumb -1 damage, cannot use spells greater than 4th level
10-11 Average -
12-13 Smart +1 to-hit, use technological devices and spells easily
14-15 Brilliant +1 to-hit and damage, 40% detect secret doors, use technological devices and spells easily
16-18 Genius +2 to-hit and damage, 60% detect secret doors, 40% detect traps, use technological devices and spells easily
Being smart makes it easier to slay monsters and murder people. EPT uses three difficulty classes of spells instead of OD&D's six spell levels, so I doubled the listed limits here and under Psychic Ability.
3-7 Weakling -2 on hit dice, 30% revive chance, 40% magic healing failure
8-9 Puny -1 on hit dice, 40% revive chance, 20% magic healing failure
10-11 Average 50% revive chance
12-13 Healthy +1 on hit dice, 60% revive chance
14-15 Very Healthy +1 on hit dice and damage, 70% revive chance
16-18 Robust +2 on hit dice, +1 on damage dice, 90% revive chance, magic healing +1 pip per die
Doing your cardio also makes beating up people easier. "Revive" refers to magical raise dead type effects.
3-7 Non-Psychic Cannot use spells or magic
8-9 Barely Psychic Cannot use spells greater than 2nd level
10-11 Average Psychic Cannot use spells greater than 4th level
12-13 Somewhat Psychic +5% spell casting chance
14-15 Quite Psychic +10% spell casting chance
16-18 Highly Psychic +15% spell casting chance
To use the Psychic Ability stat in my own campaign I'd need to convert my overcasting chart to d% or d20. It's currently a 2d6 chart based upon the spell throw rolls from Chainmail.
3-7 All Thumbs -1 to-hit and damage, Natural 1-4 on to-hit roll indicates wrong target (i.e. friendly) struck
8-9 Clumsy -1 to-hit, Natural 1 or 2 on to-hit roll indicates wrong target struck
10-11 Average Natural 1 on to-hit roll indicates wrong target struck
12-13 Clever +1 to-hit
14-15 Dexterous +1 to-hit and damage
16-18 Agile +2 to-hit and +1 damage
NB In combat characters of Dex 11 or less would need to roll d20 for wrong target possibility even when casting a spell that does not normally require a to-hit roll.
3-6 Hideous May frighten others
7-8 Ugly Repugnant but not frightening
9-10 Average -
11-14 Good Looking Attractive to some degree
15-16 Very Handsome/Beautiful Turns heads on the street, frequent subject of marriage proposals and other propositions
17-18 Wildly Handsome/Beautiful May be subject to kidnapping attempts, blackmail, cash offers, etc
The 11-14 range for Comeliness squishes together three categories on the original chart that have no mechanical differences.
"Man, is there anything Jeff CAN'T do when it comes to gaming? This guy is like a critical 20 every roll. Jeff can bite the heads offa five game geeks, including their sorry-ass DM, and spit 'em into a large duffel bag ONE AT A TIME!...that's just the kind of messed up bastard he is! You think yer a gamer, punk? Well..do ya? Jeff will depants your weasel-ass right in front of your grandma."