[ExI] who should white shoot?

[Lee Corbin]

Stuart writes

> --- spike <spike66 at att.net> wrote:
> 
>> The point of the exercise is in the math.  I found it quite astounding to
>> pose a question that involves only thirds, and end up with an answer (still
>> unverified) that involves sevenths and eighths.  Sevenths!  Isn't that an
>> oddball number to pop up?
> 
> Congratulations, Spike, you have rediscovered Bayes Law. The good reverend
> would be pleased. :-) 

You act as though Bayes' Formula or Bayes' Rule was unknown
before its mere formalization by Bayes. It's a very elementary common
sense application of mathematical reasoning, and it's possibly even
insulting to Spike to imply that he hasn't been able to solve
problems such as this ever since he was in high school. 

If there are two trays of cookies held over your head, and you know
that 9/10 on one are burnt, and just 8/10 on the other tray are burnt,
then it does not take Gauss to conclude that if you reach up and get
a non-burnt cookie, the odds are two-to-one that you selected from
the 8/10 tray. (In more difficult problems, naturally you have to mentally
weigh and probably calculate the proportions more carefully, but the
principle based upon equal chances for all cookies is the same.)

What Bayes *really* did was far, far more important.

Lee