SAT Sample Statistics and Margin of Error study notes

A sample estimate is not the exact population value. A reported margin of error gives a range around the estimate, expressed in percentage points. The range summarizes sampling uncertainty under the poll’s assumptions; it is not a promise that the true value must lie there.

Worked example

A poll reports 52% support with a margin of error of 4 percentage points. What interval does that describe?

Subtract and add 4 points: 48% to 56%. Notice that you add percentage points, not 4% of 52.

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