[Wallaby]

I suspect that your slightly lower probability of a Bush win (67% instead of 68%) is due to an error of requiring more than 270 votes, rather than at least 270 votes. When I ran the simulation using that incorrectly higher requirement for victory, my results matched your analysis for the probability.

[Lonesome in Massachussets]

Wallaby is absolutely correct.

The way I calculate CDF, CDF(n) is equal to the probability that Bush equal or exceed n. So it is consistent with the analysis. BTW, while we shouldn't take this too seriously, R.W. Hamming, Professor at the Naval War College, made the point that the purpose of scientific computations was insight, not answers. (Of course poor analysis or simulation lead to misleading insights.)

One interesting insight is that there is an approximately 1-percent (0.0098) chance that the race will end in an electoral college tie 269-269. I believe the House has decided the election only once before, selecting Thomas Jefferson over Aaron Burr in 1800. The House votes by "delegation" each state getting one vote. Since the delegations are overwhelmingly Republican, this sort of means we should likely award the election to W in case of tie.

If the election is close it is likely that Kerry will have the majority of the popular vote since Democrats are more concentrated in a few populous states which they win by large margins. It'll be SO much fun to hear the NYT and CNN squeal.