As requested, here are the calculations regarding Stats and how they effect your Battle Ability.
Note:
Before you look at this please know that I did not come up these calculations myself, however I have tested all stat calculations and found them to be true. I have not had time to check the ability calculations or make a more in-depth guide yet so please bear with just the raw calculations for the time being.
Stats
1 Str = 2 P.Atk for Melee and 3/8(or 0.375) P.Atk for Range
1 Vit = 2 P.Def and 30 Max HP
1 Agi = 0.5 Evasion
1 Int = 2 M.Atk and 30 Max MP
1 Wis = 2 M.Def, 3/8(or 0.375) M.Acc, and 0.5 M.Res
1 Dex = 13/8(or 1.625) P.Atk for Range, 0.5 Accuracy, and 1/8(or 0.125) M.Acc
1 Luck = 0.2 Critical Ratio
Battle Abilities
HP = Vit*30 + Lv*20
MP = Int*30 + Lv*20
P.Atk(Melee) = Str*2 + Lv
P.Atk(Range) = (Dex*13 + Str*3)/8 + Lv
Accuracy = Dex/2 + Lv
M.Atk = Int*2 + Lv
P.Def = Vit*2 + Lv
Evasion = Agility/2 + Lv
Atk Spd = Fixed 100
M.Acc = (Wis*3 + Dex)/8 + Lv
M.Def = Wis*2 + Lv
M.Res = Wis/2 + Lv
Mov Spd = Fixed 120
HP Regen = Fixed 5%
MP Regen = Fixed 5%
Block Per = Fixed 0%. Increased with a Shield.
Crit Ratio = Luck/5 + 3
Cast Speed = Fixed 100.
HP Recov = 48 + Lv*2
MP Recov = 48 + Lv*2
Block Def = Fixed 0. Increase with Shield
Crit Power = Fixed 80%
Cast Speed = Fixed 100.