WTH does agility do?

[Wickedbane]

Agility: Agility affects how quickly you can learn some defensive skills, how difficult it is to hit you as well as how much damage you take when you are hit. The true effect of Agility is often debated. One of the three key factors for Monks is their AC and many Monks max this stat out in the hope of helping obtain a higher one at later levels. The amount gained is very minimal however and we recommend increasing your damage output over a minor armor class increase.
EQTHIEVES.com

Agility - Helps you avoid incoming attacks. Plays a part in avoidance armor class (which you cannot see, but trust me, it's there).
Almersguide.com

Agility (AGI)
Affects: Dodge, Defense, Avoidance Armor Class*, Parry?, Run speed (below 75).
Agility determines how much melee damage enemies inflict. Below 75 agility causes a large AC hit.
Max (cap): 255 ?
Brad McQuaid: "AGI: affects how quickly you can learn some defensive skills, how difficult it is to hit you as well as how much damage you take when you are hit "[3]
It's generally agreed on that AGI has very minimal effects on gameplay as long as it is at least 75, and that it is one of the least important stats to increase for any character.
P99wiki.com

Can anyone tell me how agility helps with dodge, defense and avoidance? Does having a high agility number effect the amount of times you're hit or the amount of damage you take? And by how much?

I know agility gives AC but if that's all it does why have the stat?

Does agility and AC work hand in hand? High AC and high agility = less damage taken?

Or is it each mob has a min/max dmg and just hits you randomly for whatever amount of damage.

Does having high agility improve you're dodge stat? If your dodge is 155 with high agility would it be 175 or 190?

Is there a formula to calculate you're avoidance?

Is there a formula to calculate how much AC you get per agility point?