Teacher resources and professional development across the curriculum
Teacher professional development and classroom resources across the curriculum
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Confidence Interval Calculator for Means
Can We Be Confident?
Pollsters make reference to the results of a poll in terms of confidence. They say they are 95%, 90%, 75% confident of their results. No one, at any time or under any circumstances, can be 100% sure of a poll's accuracy.
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.
What's a Confidence
When a pollster is 95% confident, that means this: If the poll was repeated 100 times, then in 95 of the polls, the percent of people who said that they supported a particular candidate would be within the margin of error of the percent who said that they supported that candidate the first time. Of course, that means that in 5 polls, the pollster could expect results that were nothing like the original results.
is inspired by programs from Against All Odds: Inside Statistics.