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Topic: Electoral college probablities
Replies: 9   Last Post: Nov 2, 2000 6:02 PM

 Messages: [ Previous | Next ]
 Robert Israel Posts: 11,902 Registered: 12/6/04
Re: Electoral college probablities
Posted: Nov 2, 2000 4:26 PM

In article <3A002FEC.4AEE86C3@echip.com>,
Bob Wheeler <bwheeler@echip.com> wrote:

>If p is the popular vote proportion and if p is
>the same for all states, then the expected
>electoral total is 540p with a variance of
>540p(1-p). Assuming normality, this gives the
>probability of erroneous electoral result as 0.32
>when p=0.51, 0.085 when p=0.52, and 0.03 when
>p=0.53. Hence, a popular-electoral mismatch seems
>unlikely when the popular vote exceeds 50% by two
>or more points.

Unless I misunderstand your assumptions here, this is wrong.
You seem to be saying that each state has probability p of
a "correct" electoral vote. This would work if the
state's electoral vote was decided by one randomly chosen
voter, but that's not what happens.

The problem as I interpreted it had p = 0.5, i.e. each
voter votes "randomly" with equal probabilities for the
two candidates. And the conclusion is that the probability
of a mismatch is about 0.2.

Robert Israel israel@math.ubc.ca
Department of Mathematics http://www.math.ubc.ca/~israel
University of British Columbia

Date Subject Author
10/30/00 Peter L. Montgomery
10/30/00 William L. Bahn
10/30/00 Bart Goddard
10/30/00 David Einstein
10/31/00 Bob Silverman
10/31/00 Steven E. Landsburg
10/31/00 Robert Israel
11/1/00 Bob Wheeler
11/2/00 Robert Israel
11/2/00 -Mammel,L.H.