Jeff Sauro • January 4, 2008

Use this calculator to understand how sample size changes will affect the confidence interval around a completion rate. For more context, see the Sample Size article.Known Users: Most Likely Completion Rates

Known Minimum Completion Rate: Unknown Users

The calculations are derived from the Adjusted-Wald binomial confidence interval.

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Confidence Interval Calculator for a Completion Rate

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A Brief History of the Magic Number 5 in Usability Testing

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