QUOTE (Thanee @ Oct 15 2012, 04:57 PM)

That's not rare. The SR situation you have been describing is more like once-in-a-lifetime rare.
Let me describe another scenario.
Every five minutes you, personally, have a 0.5% chance of receiving $1.
On average, every week, you'll get $10 added to your bank account.
What are the odds of receiving
no money after one week?
That's a super rare chance of happening are so rare as to occur once in a lifetime.
Right?
Wrong.
One person in 24,471 will experience this every week.
That's not a very big number.*
Why are these numbers relevant? Remember Team Fortress 2's old drop system?
I'll dig it up for you.
QUOTE
Valve calculated the average time a regular Team Fortress 2 player played, then came up with a standard time which was used as a marker or set point. Every 25 minutes of gameplay, the game calculated a random number to determine whether the player would receive a weapon. If the player was lucky (25% per item chance), then they would find a randomly chosen item. If the player was unlucky (75% chance), then they would receive nothing and the timer would reset. In addition, there was a separate timer which ran on a 15,430 second (4 hours, 17 minutes, and 10 seconds) interval which gave an additional 1 in 28 chance of receiving a hat. The average time for finding a single item was 1 hour and 40 minutes (including duplicates). Since weapons were granted via a random number generator, experiences varied.
A friend of mine was one in 2,000,000 people to receive exactly 0 drops over a two week
game time period (running the game 24 hours a day, 7 days a week).
(I forget the exact duration and known probabilities at the time, but it worked out to a 1 in 2 million odds. He also knew someone else who was experiencing the same thing). That's why the current system is a "random duration to next drop" system.
Welcome to practical statistics.
*If everyone in the world had this offer, there would be 285,000 people would experience this on a weekly basis.