EV and Variance

[JoeyT]

It has been awhile since I did much math, and I'm sure this has been discussed but I can't find a good answer to it... so if someone can point me to a resource or just answer this I would greatly appreciate it. Basically I want to know that given...

EV of E per some unit time (an hour or 100 hands or whatever)
Variance V for that same unit time
# Units of time T

What are the chances that you make or lose $X over T units of time with said E and V?

So like, if your EV is $10/hr and your variance is $50/hr, what are the chances over a given 10 hours you'll make at least $100, or lose at least $100, or whatever. Also, what is a reasonable variance for a TAG in llhe games?

Thanks.