Warrior - Crits How do they work?

[Stonewallx39]

I’ve searched The wiki and it doesn’t seem to have much to say about Warrior Critical hits and crippling blows beyond that they exist.

My questions:
1. How do critical hits work? Is it totally random based on number of swings, so faster weapons would have more crits (in a given time period) or calculated some other way?
2. Is there a stat that boosts probability of crits or how hard they hit for? I know dex for ranger bow crits, is it the same for warriors? Or possibly strength will impact?
3. Is the max 2x normal max hit (my max is 28 at lvl 14 but I’ve crit for 56) will dex or strength modify this?
4. How do crippling blows work? What’s the story do they do anything special such as extra dmg beyond crits or cause a stun? The text says ”soandso staggers” but I e never had a really good crippling blow so I cant say.