The arena system is the single most competitive part of World of Warcraft. It brings out all the skill and dedication in people and makes for epic battles. Its split up in 2v2, 3v3, and 5v5. After the season qualifications are done the playoffs begging. This part is only for 5v5 but the idea blizzard has is to face the worlds best arena players in a live tournament at Blizzcon this year.
The thing that makes arena so good and competitive is the rating system. Its based on the widely popular Elo chess rating system. It basically works based on the current rating you have. Your team is teamed up against other teams of somewhat similar rating, when you win against a stronger team you get a lot of point and if you win against a lesser team you get less to none points. If you lose to stronger team you lose very few points however if you lose to a lesser team you will lose a lot of points and thus falling in rating. In World of Warcraft, rating at the end of the week determines how much arena points you get and those you use to buy items. The items can be found here: Weapons | Armor.
The way that the points are calculated is based on this formula:
Team Rating Arena Point Formulae
X = Team Rating, Y = Arena Points
If X>1500: 1511.26 /(1+1639.28*Power(2.71828, -0.00412*X))
Else: Y =0.22*X + 14
The 2v2 and 3v3 penalties are 76% for 2v2 and 88% for 3v3
As you see this is very hard to calculate without using the Boxspherical Arena Calculator.
