You can view your character's stats in the inventory screen. As your character levels up, his/her health and base damage will increase accordingly and will also allow you to equip better weapons and armor. Your stats will also be affected by equipment engravings. These are bonuses that can be added to a weapon or armor with the help of a blacksmith.
Total amount of damage that can be taken before dying. Value is based on the current level and modified by item perks.
Amount of Protection from damage received. Value is based on the total Armor from gears. Can be modified by perks and Mastery Abilities.
Average damage dealt with melee weapons. Value is based on the current level and melee weapon DPS. Can be modified by perks and Mastery Abilities.
Average damage dealt with assassinations and Knock Outs. Value is based on current level. Can be modified by perks and Mastery Abilities.
Average damage dealt by ranged weapons. Value is based on the current level and melee weapon DPS. Can be modified by perks and Mastery Abilities.