Using colorful graphs, this page demonstrates how confidence intervals work. New Confidence Interval Applet Visitors to this site can manipulate a Java applet in order to see various levels of confidence intervals.
Pollsters make reference to the results of a poll in terms of confidence.
It's actually possible to determine the level of confidence and margin of error prior to carrying out a poll. A higher level of confidence always requires a larger sample size. The range of numbers that fall within the two ends of the margin of error is referred to as the confidence interval. The interval reflects the calculated average and those numbers that might fall outside that average. Of course, that means that in 5 polls, the pollster could expect results that were nothing like the original results.