Edgewood of Karameikos
Rolling ability scores is done as follows:
Roll three sets of a straight 3d6, seven times, discarding the lowest result in each set. If in any set, the total of the ability score modifiers is equal to or less than -2, discard the set and roll another.
If that is too complicated, just take the Elite Array (15,14,13,12,10,8) or use 25pts. in the point buy system method in the DMG.