I was wondering the rolls you see to pass the various checks they are already taking into account characters abilities & buffs ? e.g if a rogue is sneaking around a guard & needs say a 10 to be successful then I take it a plate wearing fighter needs a 19, or if you are moving a group the game works out averages & spits that out as the roll required say a 14 ?

This may be common knowledge I just hadn't seen it clearly demonstrated apart from in an individuals case & I just assume all the buffs etc are built into the roll required - I hope Im making sense......