An attack roll represents a character's attempts to strike an opponent on the character's turn in a round. When a character makes an attack roll, he or she rolls 1d20 and adds his or her
attack bonus. If the result equals or beats the target's
Defense, the character hits and deals
damage. Many modifiers can affect the attack roll.
If the character is not proficient in the
weapon he or she is attacking with (the character doesn't have the appropriate
Weapon Proficiency
feat), that character takes a -4 penalty on the attack roll.