Kiley and Company responds with information on the methodology of the poll showing Libby Mitchell ahead of some of the other Democratic gubernatorial candidates:
301 likely Democratic primary voters in the state of Maine were interviewed. Trained professionals, working from a central, monitored location, conducted the interviews by telephone during the evening hours of July 21 and 22, 2009. Respondents were randomly selected from an up-to-date file of Maine voters who have cast ballots in at least one recent Democratic primary election. They were screened to confirm that they are likely to vote in the Democratic primary in June 2010. County and gender quotas were imposed to ensure the sample population is representative of the Democratic primary electorate.
The margin of error for a dichotomous question for a sample of this size is approximately ±7 percentage points.
I assume the margin is 95 times out of 100.