If I have my players roll 3d6 to get their ability stats they should have an average stat of 10.5 right?
What happens when it becomes a roll of 4d6 drop the lowest?
What happens if I allow them to reroll all ones (still 4d6 drop the lowest)?
I've been told that roll 3d6 is equivalent to 15 point buy, and 4d6 drop lowest with 20 point buy.
I always use 20 pt buy. I feel is good enough to give you 18-20 if you desire but sacrificing good enough.
My next character will be intentionally a melee small halfling with 16-2 STR. I think that's enough if you want to hit enemies and not overwhelm them.
Unless you play high powered game, 14 is good enough.
From http://rumkin.com/reference/dnd/diestats.php
Roll: 3d6
Statistics
Min: 3
Max: 18
Avg: 10.50
Std Dev: 2.958
Roll: 4d6
Statistics
Min: 4
Max: 24
Avg: 14.00
Std Dev: 3.416
On the other hand the advantage of rolling is luck. If you can't switch the rolls, you might end up playing something you don't like. Some people just get better results. I've seen people roll and get 15 or higher on each stat, while others get barely a 13.
This creates disparities that could make players feel their character is weak and useless. You feel like cheated by the system and there's nothing you can do about it.
I totally agree and dislike rolling for stats, but it's what the players want. I want to form a stat array for those who roll poorly.
I've been told that roll 3d6 is equivalent to 15 point buy, and 4d6 drop lowest with 20 point buy.3d6 is significantly worse than 15 point buy. It's equivalent to basic NPC stats (13/12/11/10/9/8) or monster stats (11/11/11/10/10/10), which are 3 point buy. 15 point buy is equivalent to heroic NPC stats (15/14/13/12/10/8). I'd guess that the heroic NPC array was an attempt to emulate 4d6 drop lowest (back in 3.5), but they got the math wrong. 20 point buy is probably closer.
The average is of less concern than what the guy actually rolled. The average would be brought up by any reroll rules you have for an unacceptably low set of rolls. In many cases, these rules are made up on the spot when a player has a run of especially bad rolls for ability scores.
And if the player was exceptionally lucky with the rolls, his effective point buy could be much higher than the average. You can easily add up the effective point buy equivalent of any rolled stats, perhaps applying a minor discount to account for the fact that the player cannot tinker with the numbers beyond arranging them as desired.
It basically makes almost no sense rolling. Because if you want to adjust extreme bad and good luck, might as well use pt buy.
If you adjust only extreme bad luck you end up with 3 players with average rolls and 1 player who's a MAD class with 16 in all stats, and it's basically good at everything.
If you make a simple rule with pt buy of maximum 18 with racial adjustment or 16 with racial, you force players to make more well rounded characters.
As long as you don't play in an Mythic super optimized campaign a 16 in your main stat at level 1 is more than enough.