Hi guys.
Magne Aldrin furnished the list with some topical yet statistically
pertinent information. Martin Sewell posed an equally valid question, to
which Dave Walshaw's responses were particularly valid from a
statistical point of view. Although Allstat isn't a discussion list, I'd
have been disappointed not to have seen what had to be said on this
issue.
So Alison is right, shouldn't there be a discussion list for stuff like
this? And if there is, do any of you lot know of such a list?
Best wishes,
Fen Scott.
> -----Original Message-----
> From: A UK-based worldwide e-mail broadcast system mailing list
> [mailto:[log in to unmask]] On Behalf Of Macfarlane, Alison
> Sent: 09 June 2006 18:17
> To: [log in to unmask]
> Subject: Re: World Cup probabilities
>
> As the listowner often reminds us this is not a discussion list so
could
> statisticians interested in football please set up your own football
> statistics discussion list and spare the rest of us.
>
>
> Alison Macfarlane
> Department of Midwifery
> City University
> 24 Chiswell Street
> London EC1Y 4TY
> Phone (0) (44) 207 040 5832
> Fax (0) (44) 207 040 5866
> Email [log in to unmask]
> -----Original Message-----
> From: A UK-based worldwide e-mail broadcast system mailing list
> [mailto:[log in to unmask]] On Behalf Of David Walshaw
> Sent: 09 June 2006 14:14
> To: [log in to unmask]
> Subject: Re: World Cup probabilities
>
> >At 17:51 08/06/2006 +0200, Magne Aldrin wrote:
> >>Those of you that are interested in football in addition to
> >statistics
> >>may have a look at the web-page http://vm.nr.no containing winner
> >>probabilities for each team during the FIFA World Cup in Germany.
The
> >>probabilities will be updated daily during the tournament. The
> >>probabilities are based on a Poisson model. The model is estimated
by
> >>maximizing a penalized and robustified Poisson-likelihood, based on
> >>expert opinions before the tournament starts and the match results
> >>during the tournament.
> >
> >Why not simply use betting odds? http://www.oddschecker.com
> >
> >Regards
> >
> >Martin
>
> Well, admittedly as a non-expert, I would say because the
probabilities
> at http://vm.nr.no/indexEng.html are free of several sources of bias
> present in the betting odds:
>
> 1. Bookmakers odds are determined partly by bets placed, which are
> influenced by subjective probability beliefs, but also other factors
> such as patriotism. This is particulary apparent in a tournament
between
> nations. So, for example, if I wanted to bet on England, I would
expect
> to get a better price from a German bookmaker than an English one!
>
> 2. When betting odds are converted to probabilities, they sum to more
> than 1, in order to allow the bookmakers to have an expected profit.
> There is no information on how the adjustments from probabilities to
> odds are distributed over probabilities of different size, so reliable
> recovery of the probabilites is not possible.
>
> Finally, suppose you are in the situation where you want to place a
bet
> on the outcome of the World Cup, but you are out of touch with
football,
> how do you assess which bets are good!? The site recommended by Magne
> seems to be exactly what you need.
>
> Regards,
>
> Dave
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