This article presents a statistical analysis of the results of the 2000 U.S.
presidential election in the 67 counties of Florida, with particular
attention to the result in Palm Beach county, where the Reform party
candidate Pat Buchanan recorded an unexpectedly large 3,407 votes. It was
alleged that the "butterfly ballot'' had misled many voters into
voting for Buchanan when they in fact intended to vote for Al Gore.
We use multiple regression techniques, using votes for the other candidates
and demographic variables as covariates, to obtain point and interval
predictions
for Buchanan's vote in Palm Beach based on the data in the other 66 counties
of Florida. A typical result shows a point prediction of 371 and a 95% prediction
interval of 219--534. Much of the discussion is concerned with
technical aspects
of applying multiple regression to this kind of data set, focussing on
issues
such as heteroskedasticity, overdispersion, data transformations and
diagnostics.
All the analyses point to Buchanan's actual vote as a clear and massive outlier.