User blog comment:Sneak+stab/50%+60% is not 110%/@comment-4659931-20111214121522

I believe your 50% resistance is added to the resistance your character would normally be allocated, which may be quite small, like a troll's, or large, like a flame atronach's, and is not a percentage of the attack itself. In effect your potions and armour increase the number of times the attacker needs to hit you, which in turn depends on who is attacking and how powerful their attack is. You will never be immune to the attacks, it just means it takes a little bit longer to kill you. (I think...) I have no idea whether the items are accumulative, but they make me feel safer.