Are the odds (ever) in my favor in this raffle?
April 19, 2012 10:39 AM Subscribe
Are the odds in this raffle significantly better than last year?
posted by madajb to Science & Nature (17 answers total) 1 user marked this as a favorite
An organization I am part of holds an annual raffle.
This year, the price to participate has gone up quite a bit, but the rules have also changed. I'm trying to figure out if it is a better or worse deal but using vaguely remembered probability formulas isn't helping.
Last Year :
2 big prizes to win.
18,000 tickets sold.
One prize per ticket(meaning once your ticket is pulled, it's out of the drum).
They claim your odds of winning a big prize were 2 in 18,000.
12 big prizes to win.
Maximum of 10,000 tickets to be sold.
Multiple prizes per ticket (meaning all tickets go back in the drum for each prize)
They claim your odds of winning a big prize are 12 in 10,000 for a roughly 11 times greater chance of winning a big prize.
Last year, there were a total of 26 prizes to be won.
This year, there are 62 total prizes.
Now, here's the rub.
Last year, $10/ticket.
This year, $100/ticket.
I'm trying to work out the following:
1) If the odds are actually as they say (12 in 10,000/2 in 18000)
(They seem not, especially the 18,000, for reasons I can't explain)
2) If the odds are increased, are they increased enough to cover a 10x jump in price.
3) What the overall odds are of winning any prize compared to last year.
Any stats people out there willing to help?
Showing your work would be great so I can see where I went wrong but if you plug it into Matlab, that's fine too