# The Naked Scientists Forum

### Author Topic: How is the odds of winning the lottery calculated?  (Read 3004 times)

#### diverjohn

• Jr. Member
• Posts: 35
##### How is the odds of winning the lottery calculated?
« on: 20/08/2011 18:24:04 »
Hello Everyone:
This morning I read an Associated Press article about a woman who won 4 major lotteries over 13 years, totalling US\$ 20.4 million. The odds of one person winning 4 lotteries was declared to be about 1 in 18 septillion.
I only did one semester of stats in University, but recall much debate about calculating odds of winning versus odds of not winning.
Can someone more educated in this field guide us to how such calculations of winning 4 times are done?
The original article is at this link?
http://ca.finance.yahoo.com/news/Meet-luckiest-woman-world-forbeswp-2208865254.html [nofollow]
« Last Edit: 23/08/2011 11:02:39 by chris »

#### Geezer

• Neilep Level Member
• Posts: 8328
• "Vive la résistance!"
##### Re: How is the odds of winning the lottery calculated?
« Reply #1 on: 20/08/2011 19:06:06 »
I saw something on the telly recently about a major hole (since closed) in a lottery system that was allowing people to game the system, although this case does sound a bit different.

This one also smells distinctly fishy

#### RD

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##### Re: How is the odds of winning the lottery calculated?
« Reply #2 on: 20/08/2011 20:13:13 »
They are called a "lottery tickets" but are more like a scratchcard than a true random lottery (with numbered balls): the winning tickets are identifiable before they are distributed ...
http://www.wired.com/magazine/2011/01/ff_lottery/all/1
« Last Edit: 20/08/2011 20:22:03 by RD »

#### CliffordK

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##### Re: How is the odds of winning the lottery calculated?
« Reply #3 on: 20/08/2011 21:07:55 »
Most interesting.
I've always avoided the scratch-it tickets because they are always stacked against the individual.

And...  now with reports of fraud....

Yes, there are LOOSERS.

Say the odds are 1:1,000,000 of winning a large jackpot.
Then half of the jackpot tickets are stolen.

Suddenly the odds that the rest of the "public" get are 1:2,000,000

I have no doubt there is an insider in many of these stories, for example the store that sold Ms. Ginther the winning tickets (and mysteriously closed).  That person needs to be tracked down and prosecuted if they received any kind of kickback.

As far as the drawings for the "pick the number" lotteries.
Certainly any winning of \$10 Million or more would be life altering.
However, I never consider it "worth-it" to buy a ticket for a 1:100 Million chance to win \$10 Million.
It gets more complicated when it becomes a 1:100 Million chance to win \$200 Million.

#### Bored chemist

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##### Re: How is the odds of winning the lottery calculated?
« Reply #4 on: 21/08/2011 09:47:11 »
"I've always avoided the scratch-it tickets because they are always stacked against the individual."
So, just the same as the lottery then.

#### CliffordK

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##### Re: How is the odds of winning the lottery calculated?
« Reply #5 on: 21/08/2011 18:10:22 »
"I've always avoided the scratch-it tickets because they are always stacked against the individual."
So, just the same as the lottery then.

Well...  Yes.

As mentioned above, with the lottery...  one can jump in when the odds of payout goes to \$2 per \$1 invested.  But, even that is complicated because the overall amounts are outrageous, and the government takes taxes (on top of their cut)...  say 50%.  And, they have the lump sum vs annuity...  and perhaps take more out if one requests the lump sum.  Thus, the break-even point is probably closer to the point at 4x the odds.

#### grizelda

• Hero Member
• Posts: 740
##### Re: How is the odds of winning the lottery calculated?
« Reply #6 on: 21/08/2011 22:39:32 »
So both these statements are true: You can't win if you don't play. You can't lose if you don't play.

#### The Naked Scientists Forum

##### Re: How is the odds of winning the lottery calculated?
« Reply #6 on: 21/08/2011 22:39:32 »