This is a nonparametric test of the hypothesis that the two subpopulations, machine and hand counts, come from the same distribution.

        Wilcoxon rank sum test

data:  (Clinton..d - Obama..d)[machines] and (Clinton..d - Obama..d)[!machines]

W = 422, p-value = 0.0001150

alternative hypothesis: true mu is not equal to 0

95 percent confidence interval:

 0.1186801 0.2903706

sample estimates:

difference in location

             0.2027052

The test is astonishingly simple: you rank the combined population and add up the ranks of the elements of one of the two subpopulations, and then look up in a table. This is telling us that the Hillsborough hand counts and the machine counts come from different populations at 99.99% confidence level.

We have met the enemy, and he is us — Pogo