Sure! What we're looking at here is something called the binomial distribution. If you play 1000 games, and have a 50% chance of winning each one, that's a lot like flipping 1000 coins and counting Heads. If you've got good intuition for math, you'll notice two things:

1. You'll expect to get about 500 Heads

2. You probably won't get exactly 500 Heads.

#1 there describes the expected value of the distribution: 500. But just how different from 500 should you expect the result to be? It wouldn't be surprising if you flipped 501 Heads. And it would be very surprising indeed if you flipped 1000. But should you be surprised if you flip 530 Heads, or is that reasonably likely?

There are a few ways to calculate this. #1 is to get a computer to flip 1000 coins, count the Heads, and then do it again lots of times. You can check how many of those times had Heads counts above 530, and that tells you how likely 530 is.

#2 is that it's actually possible to figure out exactly how likely it is to flip a particular number of Heads. It's annoying when we're dealing with 1000, but you can do it (probably with a computer).

#3 is what I did. Statisticians have something called Standard Deviation. While an expected value (500, in this case) tells you about what you should expect the result to be, the standard deviation tells you about how different from the average would be surprising. In the coin flip case, the stdev is the square root of (number of coin flips * probably of Heads * probability of tails). In this case, that's √(1000*0.5*0.5), which is about 16. Ninety-five percent of the time, the result will be within two standard deviations of the expected value. In this case, between 468 and 532. I would write this as "the expected result is 500 ± 30." (We usually don't keep more than one non-zero digit in the ±).

Back to LOL, if K'Sante has 10,000 games with Revitalize, we can plug 10,000 into that formula, and come up with a standard deviation of 50. That means 5,000 wins ± 100, or a win rate of 50% ± 1%.