Short answers, pulled from the story.
A statistic in a role-playing game is a piece of data representing one particular aspect of a fictional character. It is usually a unitless integer, though in some games it takes the form of a set of dice. Most games divide statistics into several categories, including attributes for natural characteristics, skills for learned abilities, and powers for unique qualities.
Champions, published in 1981, introduced the character point system as a means of purchasing attributes and skills rather than assigning them randomly. The system was later adopted most prominently by GURPS. In Champions, character points also serve as experience points for improving a character during play.
Attributes represent natural, in-born characteristics common to all characters, such as strength or charisma, while skills represent learned abilities specific to a character. Most games hold attributes fixed at character creation, whereas skills can almost always be improved by spending experience points or levelling up. Attribute ranges typically run from as small as 1-5 to as large as 1-100 depending on the system.
Over the Edge was the first major role-playing game to use traits as a primary statistic type. Traits are broad areas of expertise chosen freely by the player during character creation rather than selected from a predetermined list. Castle Falkenstein and HeroQuest later used traits as their only form of statistic.
Avalon: The Legend Lives is noted as the first text-based multi-user role-playing game to offer a developed profession and skills system. When the game launched, it offered around 30 skills with approximately 17 abilities each, covering areas from Riding and Perception to Thievery and Demonology. By 2015, Avalon had expanded to 66 skills with 2,194 distinct abilities developed over 26 years.
Min-maxing in role-playing games is the practice of selecting disadvantages with little practical effect on play in order to collect character points, then spending those points on powerful advantages. It is a common criticism of character point systems. The practice exploits the mechanical structure of point-based design rather than engaging with a character's limitations in play.