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Confidence Interval for a Proportion

From the number of successes, the sample size, and the confidence level, get the sample proportion, standard error, z*, margin of error, and the interval — with steps.

p̂ ± z*·√[ p̂(1 − p̂)/n ]
successes x sample size n confidence %

Enter the number of successes, the sample size, and the confidence level (e.g., 90, 95, 99). Uses the normal (Wald) interval.

Results

Confidence interval
—
—
Sample proportion p̂
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Standard error
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z*
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Margin of error
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Lower limit
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Upper limit
—

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