Editing Probability (section)

==Rolling for successes/hits==
Relevant for: Shadowrun, old WoD, new WoD, others

===What are the odds of me succeeding with X many dice?===
You can work out the chances of every individual result, but the quickest way to figure out if you're going to get any successes at all is to take the Inverse of rolling no successes at all.

So, you've got 4d10 and you need an 8, 9 or 10 to succeed? You've got a .3 chance of a success on one die, meaning you have a .7 chance a failure on one. You're rolling four dice, so the odds of all of them being failures is .7^4, or 0.7*0.7*0.7*0.7, or 0.2401. The inverse of that, the odds of getting anything other than zero successes, is 0.7599.

Incidentally, if you're working with that Target Number 8 in the last paragraph and you want a quick way to work out your chance of success... The odds of failing outright with two dice are 0.49, or about 1/2. That means the odds of failing with four dice are about 1/4. Six dice gives you 1/8, eight gets you 1/16, or 15/16 chance of getting at least one success. Repeat as many times as you like.

There are tables floating around, but I cannot into embedding images.
http://wiki.white-wolf.com/exalted/index.php?title=Dice_Probability/Heroic,_TN_7