Percentages or stats for a raffle?
 

I was wondering if there was any way to narrow down the odds on winning a raffle, without going overboard.

My friend's church is having a raffle (iPad 2) to raise money for their kids to go to church camp this Summer. I bought 5 tickets.
He said they had 50 or 60 members in their church, and most of the kids and adults were selling tickets.
He didn't know how many tickets were on a roll, but they've already gone through a roll and a half, and the rolls are about 8 or 9 inches across and the size of movie tickets.
The drawing is the 21st of May, or thereabouts, and they've been selling about a week now.

With the data I've provided, can any of y'all tell me what my chances are likely to be in winning?
If I've left anything out, let me know.

Btw, another friend says raffles are scams.
I've never heard that before. Anybody else ever hear it?

simplistic way:

how many tickets sold -

divided by

how many tickets you bought =

your odds of winning the whole thing...

if you dont know how many tickets in a roll, you'll need to find out how thick the roll of tickets is.

you may also want to find out how thick the paper is so we can guesstimate how much tickets in a roll. without that information, its a stab in the dark for everyone.

before anyone gives any formulas, its important for you to tell us whether the winning tickets go back into the draw once theyve won.

---------- Post added at 09:33 PM ---------- Previous post was at 09:31 PM ----------

also..is there just one prize? or are there numerous ipad prizes?

As far as I know, there's only one drawing and one prize.

He didn't know the number of tickets on the roll, but the tickets are about an inch and a half long, and about as thick as school poster board, or the thickness of cereal cardboard box material.
The rolls are about 8 or 9 inches across, laid flat.

There are probably 500 tickets on that roll. At least there were that many when I last handled one.

Your friend is right - raffles are a scam. But that's beside the point, really. You don't enter the raffle to win the iPod2 - you enter to help the church.

You want (# of tickets you bought)/(total number of tickets sold) = your probability of winning.
The numbers don't favor you.

If X = the number of tickets sold, and Y = the number of tickets you bought, then:

Y / X = P1

Where P1 = the probability of winning.

However,

1 - (Y / X) = P2

Where P2 = the probability of aiding the raffle organizers.

if you wanted barakas formula as a percentage, you will need to times P1 by 100. same goes with P2.

P1= your chance of winning
P2=your chance of not winning


like filthy said, your chance of winning is quite slim. if someone decides to cheat in some form or other, your chances will become slimmer.

the best way to approach this is by assuming that you are giving to the church and not expecting anything in return.i wouldnt think about winning too much to be honest. if you win, its a nice surprise and a nice bonus.

Did it look like this?
http://www.jforms.com/roll_tickets/dbl%20rl%20blu.GIF

That's a roll of 1000 double tickets. So, 1.5 rolls sold so far = 1500 tickets. You own 5, so 5/1500=0.0033, so you have a 0.33% chance of winning, assuming they don't sell any more.

---------- Post added at 07:21 AM ---------- Previous post was at 07:14 AM ----------

I would argue that they aren't a 'scam', as 'scam' implies that they're misleading people--you didn't seriously think you had a significant chance at winning the iPad, did you? :oogle:

Besides, if someone was doing a raffle for fun, and not to raise money, and you wanted to run a 'fair' raffle, you could easily do one with 100% payout--our office pools (march madness brackets, superbowl squares, fantasy football, etc) are set up this way. If all of the money going in goes towards prizes, technically, it's a fair game at that point. Mathematically, if you ran a raffle for all of the raffle money, (sell 100,000 tickets for $1, winner gets $100,000), it's technically a fair game, as your payout percentage would equal your risk. Since in this case you knew they were setting it up to raise money, you should have realized it was a given that they would be paying out less money than they took in, otherwise they wouldn't be raising any money raised.

Does that calculate to approximately a 1 in 300 chance of winning?

It does indeed. Assuming no more tickets are sold.

Freman, do you have to be present for the drawing?

We did this kind of raffle for my high school band. The "prize" was usually something donated by one of the local merchants. We would sell hundreds of tickets, (but usually less than a whole roll) draw the winning ticket out of goldfish bowl at the band concert, announce the winning number, post it all over town on bulletin boards (churches, stores, bars, American Legion, etc.) announce it in the local weekly newspaper and... and... and... NOTHING! Many years no one came forth with the winning ticket to claim the prize.:shakehead:
It wasn't an intentional scam, but I can see how it might have looked that way.

The solution was that they finally changed the rules so that the winner was drawn during intermission at the spring concert, and you had to be present with ticket in hand to win. People groused about that, too. But they could then just keep drawing tickets until they actually had a winner.:)

Lindy

Thanks for the responses, folks.

While I didn't see the whole roll, I did see that the strip my friend had, looked like the above picture posted by telekinetic, with the double row of connected tickets. He separated them and gave me the "keep this coupon" part.
So I'm assuming it held 1000 tickets.

Btw, I realized before I bought the tickets that I more than likely wouldn't win. I had gone to one of those church camps as a kid, myself. Had a good time, (got to handle a boomerang for the first time) and wanted to help some other kids have a good experience, as well.
Besides, my luck doesn't run that good. ;)

Lindy, I don't know if I'll need to be present to win, or not. I'll have to look into it.