If the press is any indication the general election of 2008 promises to be more frenetic than 2000 and 2004. A recent Time poll is already showing front runner Senator Hillary Clinton (D-NY) a 19 point favorite over Senator Barrack Obama (D-Ill) for the Democratic nomination. The Republican nomination is still up for grabs between Senator John McCain (R-AZ) and former New York City mayor Rudolph Giuliani.

Despite the buzz generated by Senator Barack Obama entering the race, the survey found that Senator Clinton would beat him for the Democratic nomination by a margin of 40% to 21%. Senator John Edwards is a distant third with 11%.

McCain, however, holds a narrow lead of 30% to 26% over Giuliani for the GOP nomination. A race between McCain and Clinton would be a virtual tie (47%-47%), according to the poll, while McCain would beat either Obama or Senator John Edwards by a 7-point margin.

Over the next year and a half there will be a plethora of polls both on the President’s approval and his potential replacement, but what do those numbers actually mean? We all see at the bottom of most polls the margin of error (+/-). Mark C. Chu-Carroll at Good Math, Bad Math explains the often misunderstood principle.

  1. The most glaring error is not citing the confidence interval.
  2. Many people, especially journalists, believe that the margin of error includes all possible sources of error. It most emphatically does not – it only specifies the magnitude of error introduced by non-deliberate sampling errors.
  3. People frequently believe that the margin of error is a measure of the quality of a statistic – that is, that a well-designed poll will have a smaller margin of error than a poorly-designed poll. It doesn’t
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