Mana: Increases the maximum mana points of a Champion. Most champion abilities cost mana to activate. This statistic scales additively; meaning that each bonus point acquired directly affects the statistic.
Mana Regeneration: Also known as Mp5 or mana per 5 seconds. This statistic determines the amount of mana that a champion regenerates over a five second period. Each champion starts with a different rate of base mana regeneration.This statistic scales additively; meaning that each bonus point acquired directly affects the statistic.
Ability Power: Increases the effectiveness of most champion abilities. Abilities in League of Legends that are affected by ability power have an ability power coefficient. This coefficient determines how much a particular abiilty will benefit from a champion's total ability power. For example, if a damage spell has an ability power coefficient of .25, every 4 points of ability power will increase the damage of this ability by 1. This bonus is added before magic resistance.
Cooldown reduction: Cooldown reduction reduces the amount of time you must wait after casting an ability before that ability can be utilized again. Ability cooldowns currently cannot be reduced beyond 60% of their base cooldown time. This statistic currently scales additively; there are imminent plans to change this into a multiplicative scaling towards an asymptote of 75% reduction.