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Lottory odds and general probabilities
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Post by
334295
This post was from a user who has deleted their account.
Post by
lankybrit
Flipping a coin is a repetitive procedure, so you can't use the same logic as a single drawing.
Can't figure out the math.
Always look at the puzzle as 1 - opposite to the way it's stated. That is:
What's the chance of me getting at least one Heads roll == 1 - the chance of me getting both rolls as Tails.
So, 1 - 25% => 75%.
The chance of you picking the right number: Let's say it's a number 1-10. You get one lottery ticket. Your chance is 1 in 10. If you buy 2 lottery tickets, your chance is 2 in 10.
If one ticket has a chance of 1 in 175,000,000. Then 10 will have the chance of 1 in 17,500,000. 1000 will have the chance of 1 in 175,000.
There's no complicated math. It's simply the overall probability of getting the winning number divided by the number of tickets.
Cheers.
Post by
ElhonnaDS
All I know, is if I DON'T buy 1000 lottery tickets, I have a 100% chance of not losing $1000 :P
Post by
MyTie
I play the imaginary lottery. My numbers are 6 - 17 - 83 - 8 - 25 - 7 - 7. I read the news, and see what the winning numbers are. They are never my numbers. If I can't ever win the imaginary lottery, why on Earth would I invest my money in something I never win? In fact, when I see the lottery numbers I can't even imagine myself having picked those numbers for any reason.
Besides, I'm a Christian, and I think gambling money is a sin.
Post by
lankybrit
I play the imaginary lottery. My numbers are 6 - 17 - 83 - 8 - 25 - 7 - 7. I read the news, and see what the winning numbers are. They are never my numbers. If I can't ever win the imaginary lottery, why on Earth would I invest my money in something I never win? In fact, when I see the lottery numbers I can't even imagine myself having picked those numbers for any reason.
Besides, I'm a Christian, and I think gambling money is a sin.
OMG - Don't do that. Don't have a set of numbers you WOULD play if you played the lottery. Imagine how you'd feel if the numbers actually came up.
Just do random tickets if you're not going to play every time.
Cheers.
Post by
ElhonnaDS
My father has a set of number he uses- his kids birthdays. He once told me that my sister and I had between us cost him about $5000 by being born a day too late- lol.
Post by
134377
This post was from a user who has deleted their account.
Post by
Magician22773
You have to look at the number of possible NON-WINNING combinations. Buying 2 tickets does not cut the odds in half, it only reduces the non-winning possibilities by 1.
With the Powerball game, there are 175,223,510 possible combinations. So your chances of winning with 1 ticket are 1 in 175,223,510. That means there are 175,223,509 ways to lose. With 2 tickets, there are still 175,223,508 ways to lose.
With 1 ticket, you have a 99.999999430885402993688473590032% chance of losing.
The second ticket increases you chance if winning by .00000512203166455910240060177%
The moral of the story...buy 1 ticket (if you are so inclined).
Post by
lankybrit
You have to look at the number of possible NON-WINNING combinations. Buying 2 tickets does not cut the odds in half, it only reduces the non-winning possibilities by 1.
With the Powerball game, there are 175,223,510 possible combinations. So your chances of winning with 1 ticket are 1 in 175,223,510. That means there are 175,223,509 ways to lose. With 2 tickets, there are still 175,223,508 ways to lose.
With 1 ticket, you have a 99.999999430885402993688473590032% chance of losing.
The second ticket increases you chance if winning by .00000512203166455910240060177%
The moral of the story...buy 1 ticket (if you are so inclined).
Totally wrong. Buying two tickets instead of 1 does double your chances of winning.
*Sigh* With 1 ticket, there are still 175,223,509 ways to lose. So, 1 way to win. With 2 tickets there are still 175,223,508 ways to lose. So, 2 ways to win.
2 is twice 1.
What you're doing is mixing chance of winning and chance of losing.
Wrong wrong wrong.
Cheers.
Post by
gamerunknown
This is more difficult to calculate than I thought because sharing a ticket will also split the winnings. The chance of splitting the winnings depends on total tickets bought, so is incalculable until all tickets are bought. As far as I'm aware, the chance of any given number coming up is an independent event. Chances of winning will increase linearly until all possible variations are bought.
Your coin problem can be resolved by treating the coin tosses as independent events and determining the probability of a 1/2 chance not occurring in two successive trials (0.5*0.5*=0.25), so p(occurring)=0.75.
A 1/175000 chance is not actually all that decent. If one bought one thousand tickets for such a lottery every day, one could expect to win every 403 years according to
wiki
.
Post by
Orranis
It's called binomial probability.
Here's a calculator.
You have a 1 in 175,000,000 chance, or roughly a 0.00000006% chance.
So buying 1,000 lottery tickets gets you roughly a 0.000006% chance. Yay.
Post by
Squishalot
It's got nothing to do with binomial probability, as long as you're selecting your own numbers.
Think about it like a lotto draw with a single ball, and numbers 1-10.
If you buy 1 ticket, you have a 1/10 chance of winning. If you buy 2 tickets, presumably, you'll get a different number to your first one, so you'll then have a 2/10 chance of winning.
The same principle applies to the Powerball. If you've got a 1-in-175,000,000 chance of winning, then 2 tickets will give you a 2-in-175,000,000 chance of winning, and 1000 tickets gives you a 1000-in-175,000,000 chance of winning, as long as you pick different combinations of numbers for each ticket. If you buy 175,000,000 unique tickets, then you can guarantee yourself a win (as well as a lot of 2nd division and 3rd division prizes). If the jackpot is high enough, that might even be profitable.
Now, as Gamer points out - this only looks at your chance of winning a share of the jackpot - it doesn't help you calculate how likely you are to have to share that jackpot with others, and whether it's worth it. It's no good buying every ticket and spending $100m to win the $200m jackpot if you're going to need to share that with 4 other people.
Post by
164232
This post was from a user who has deleted their account.
Post by
Squishalot
Haha, don't think that I didn't consider that!
Sport betting markets are a bit better - if you hunt around for good odds, you can use local and international betting agencies to arbitrage the odds (e.g. picking up 2.2:1 odds on team A in Australia, and going overseas and getting 2.1:1 odds on team B). Then if you place a buck each way, you're guaranteed a profit.
Hard to make it work though - relies on differences in punting. Saw something close to that in the Aus vs Brazil football (soccer) match back in the 03 World Cup - the Aus odds were something like 2.5:1 for an Australian win, compared to 5:1 everywhere else in the world. But in football, you need to find space in your betting for the draw, heh.
Post by
gamerunknown
That occurred due to the discrepancy in the Intrade and Betfair markets in the US elections. London investor made an honest profit from it, too.
Link here
.
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