Sampling Error (Margin of Error)

Calculate the margin of error for survey results.

Survey Parameters

Population Size (Leave blank if infinite)

Sample Size (n)

Observed Percentage (%)

Confidence Level

Error Analysis

Margin of Error

±3.10%

Confidence Interval46.90% — 53.10%With 95% Confidence

Overview

The margin of error expresses the amount of random sampling error in the results of a survey. It defines the radius of the confidence interval for the statistic.

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Pro Tips

If Population Size is very large compared to N, it can be ignored.

Fun Facts

"Doubling sample size does NOT halve the margin of error (it reduces by factor of sqrt(2))."
"Using 50% for the observed percentage yields the maximum (most conservative) margin of error."

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