Re: Risk/Probability Related Interactions with Public -

[Bob Giansiracusa <bobgian@radonc.washington.edu>]

> This morning's national news featured today's Powerball lottery drawing
> [chance of a winning $1 bet over 80 million to 1]. People are standing in
> lines across the US for up to 5 hours to place their bets. Many people are
> buying 50 to 100 tickets and more for these incredibly long odds [albeit for a
> chance to win $250 million].

I too saw this news.  However, my reasoning is a bit different.

If the odds of winning are 80,000,000 to 1, the probability of winning
is 0.99999999 - a pretty sure bet.

On the other hand, if one interprets the statement of the odds "really"
being 1 in 80 million (for a $250,000,000 win), the expected return
on the $1 investment is $ 250/80 = $3.125 - also not a bad investment.

So I say "Your point being ..." to the national news story.

 - Bob Giansiracusa
   Radiation Oncology Dept
   University of Washington Med Center