[Tutor] Can anyone help me?

bob bgailer at alum.rpi.edu
Fri Oct 28 19:31:45 CEST 2005

```At 08:08 AM 10/28/2005, Smith, Jeff wrote:
>But the odds that you will win are not impacted by the number of tickets
>that are sold in total...only the number you buy.  When you take into
>account the total number of tickets sold, all you get are the odds that
>the lottery will be won by anyone.
>
>I'm also a little confused by that def of odds.  Consider flipping a
>coin.  The probability that it will come up heads is 1/2.  That def says
>that the odds in favor of it coming up heads is 1.

Ah there's the rub. Odds are not "in favor". The odds of heads is 1 and the
odds of tails is 1. The odds therefore are the same. If you flip 2 coins
then the odds of both being heads is 1/3, ditto both tails. Odds of being
different is 1/2.

>
>Jeff
>
>-----Original Message-----
>From: bob [mailto:bgailer at alum.rpi.edu]
>Sent: Friday, October 28, 2005 10:52 AM
>To: Smith, Jeff; Tutor at python.org
>Subject: Re: [Tutor] Can anyone help me?
>
>At 07:28 AM 10/28/2005, Smith, Jeff wrote:
>>Aren't the odds just based on how many tickets you buy?  The odds aren't
>>affected by different people buying more tickets.  If only one person
>>buys a ticket in the entire lottery system, his odds of winning are the
>>same as if two people play, and the same as if 20 million play.
>
>According to the wikipedia: "In
><http://en.wikipedia.org/wiki/Probability_theory>probability theory and
><http://en.wikipedia.org/wiki/Statistics>statistics the odds in favor of
>an event or a proposition are the quantity p / (1-p), where p is the
><http://en.wikipedia.org/wiki/Probability>probability of the event or
>proposition." If you assign equal probability of winning to each ticket
>then odds are how many tickets you buy relative to how many tickets
>everyone else has bought.
>
>The probability of a ticket winning is 1 / m**n where m is the highest
>number possible and n is the number of numbers. If a lottery uses 6
>numbers each in the range 1..42 then the probability of a ticket winning
>is 1/5489031744.
>
>All of this is mathematics. Sometimes one or more tickets win. Is that
>"luck"?
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