Pureblood:
Str 11, Dex 13, Con 11
Int 18, Wis 18, Cha 16
= Dex +2, Int +8, Wis +8, Cha +6
Halfblood
Str 15, Dex 13, Con 13
Int 18, Wis 18, Cha 16
= Str +4, Dex +2, Con+2, Int +8, Wis +8, Cha +6
Abominations
Str 19, Dex 13, Con 17,
Int 18, Wis 18, Cha 16
= Str +8, Dex +2, Con +6, Int +8, Wis +8, Cha +6
Yikes, they're tough.
The way the conversion works is stat-10 if it's even, or -11 if it's odd. It's in the DMG early on, the thing about modifying races, blah blah.
Greg