My reading of the alien section of character generation is that, if the species has a Notable or Weak attribute, the roll generating that attribute is raised or lowered by 2. Thus a species with a Notable Strength who rolled a 7 who have an actual Str of 9.
However, over in this rpg.net thread of Traveller char-gen examples, it has been claimed "the racial modifiers are simply DM modifiers that apply to all rolls with that stat, and not modifiers to the actual stat." In other words, the Notable DM is applied to every roll using that Attribute in play, not when generating during char-gen. I've re-read the relevant rules section and can sort of see that interpretation, but it still seems unlikely (and cumbersome). So, which is it?
However, over in this rpg.net thread of Traveller char-gen examples, it has been claimed "the racial modifiers are simply DM modifiers that apply to all rolls with that stat, and not modifiers to the actual stat." In other words, the Notable DM is applied to every roll using that Attribute in play, not when generating during char-gen. I've re-read the relevant rules section and can sort of see that interpretation, but it still seems unlikely (and cumbersome). So, which is it?