The following table shows the result of the 2008 presidential election along with the vote predicted by several organizations in the days before the election. The sample sizes were typically about 1000 to 2000 people. The percentages for each poll do not sum to 100 because of voters who indicated they were undecided or preferred another candidate.
a. Treating the sample sizes as 1000 each, find the approximate margin of error.
b. Do most of the predictions fall within the margin of error of the actual vote percentages? Considering the relative sizes of the sample and the population and the undecided factor, would you say that these polls had good accuracy?

Transcribed Image Text:

Predicted Vote Poll Obama MeCain Gallup/USA Today Harris ABC/Wash Post CBS NBC/WSJ Pew Research Actual vote 52 53 51 51 52 52.7 42 43 46 46.0