There's no need to post thanks - send a PM if you'd like. And welcome to the forums.
Originally Posted by Keldrin
Indeed your opponent is correct.
Spell Hit stat (and miss chance) governs whether the spell lands or not. It has nothing to do with partial resists.
Spell penetration on the other hand, is the stat which helps bypass the target's resistances.
However, these days Spell Penetration is a stat reserved for mostly PvP usage, as raid mobs don't have resistances.