A lot of these equations pertain to Warcraft III in general. Where applicable they were simplified from the general Warcraft III form to DotA specific equations. Numbers are meant to be exact as how Warcraft III interprets them; when you see .14 it is not and approximation of 1/7.
Base stats
Variable
Title
Equation
Meaning
Str
Strength Total
Base Strength w/level + any items bonuses
Agi
Agility Total
Base Agility w/level + any item bonuses
Int
Intelligence Total
Base Intelligence w/level + any item bonuses
Pri
Primary Total
The number total for the primary stat for the hero =(Str, Agi, Int) depending on hero
ArmorB
Armor base
What a hero has w/o any stats or items**
ACoolB
Attack Cool down
The number of seconds a hero has to wait to attack again after attacking w/o any stats or items
Range
Attack Range
The distance a hero can attack
MSpd
Movement speed
How fast a hero moves in DotA. Max w/modifiers is 522.
DMnB
Damage Base Min
The minimum damage without stats nor items
DMxB
Damage Base Max
The maximum damage without stats nor items
Calculated stats*
Variable
Title
Equation
Meaning
HP
Hit points max
150 + (19 * Str)
The maximum a hit points a hero can regenerate to
HPReg
Hit points Regeneration
0.25 + (.03 * Str)
How many hit points a hero regains per second
Mana
Mana Max
13 * Int
The resource used to cast spells & use abilites.
MReg
Mana Regeneration
0.01 + (.04 * Int)
How much mana a hero regains per second
Armor
Armor
ArmorB + (Agi * .14)
Armor w/stats & items
DmgMn
Damage Min
DMnB + Pri
The minimim damage with stats taken into account
DmgMx
Damage Max
DMxB + Pri
The maximum damage with stats taken into account
IAS
Increate in Attack Speed
Agi
The number of seconds a hero has to wait to attack again after attacking. Note when warcraft says "Increase attack speed x%" it means increate this varible by x.
ACool
Attack Cool down
ACoolB + IAS
The number of seconds a hero has to wait to attack again after attacking.
AttSpd
Attack Speed
1 / ACool
How many times a second a hero can attack. Note by the schema laid out here when Warcraft III says "Increase attack speed x%" it means change IAS by x which effects ACool which effects this variable.
DRed
Damage reduction
1-{1/[1+(Armor*ADRM)]}
An amount of damage less taken from non-magical attacks
DPS
Damage Per Second
AttSpd*[(DmgMn+DmgMx)/2]
The amount of damage a hero will do a second before armor and other effects are taken into account
* Item modifiers & special hero modifiers are left out in the equations for the most past, but should be obvious with a little game play ** ArmorB is usually lower then what will show on a level 1 hero because of the agility modifier
