Confidence interval for a mean
Enter the mean, standard deviation, sample size and confidence level.
Result
Mean 100, standard deviation 10, n = 25 at 95% gives a margin around ±3.92.
Example
Build a basic confidence interval for a mean from sample statistics.
Mean 100, standard deviation 10, n = 25 at 95% gives a margin around ±3.92.
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Methodology
margin = z × standard deviation / √(sample size) for the chosen level.
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