You get that from perks or by default by wearing light armor?
Light armor almost always comes with stamina bonuses. 10% dodge is a perk in the end of the light armor tree.
What Im curious about is... why the hell this guys hints at needing stamina as a battle mage.
Stamina is pretty useless for any mage + hybrid imo. Why? 2 power attacks drains the whole stamina bar for me without investment. That means 5 levels of stamina is required for 1 additional power attack. Seems to me stamina is the most expensive resource for doing damage. As a hybrid involving mage your damage should come from spells, autoattack with enchanted weapons and summons imo.