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Confidence Interval Calculator for Means

This calculator is used to find the confidence interval (or accuracy) of a mean given a survey’s sample size, mean and standard deviation, for a chosen confidence level.

How To Interpret The Results

For example, suppose you carried out a survey with 200 respondents. If you had a mean score of 5.83, a standard deviation of 0.86, and a desired confidence level of 95%, the corresponding confidence interval would be ± 0.12. That is to say that you can be 95% certain that the true population mean falls within the range of 5.71 to 5.95.



Sample Size

The number of respondents who answered the question.


Observed Mean

The mean average score for the question you are interested in.


Observed Standard Deviation

The standard deviation of the mean average score.


Confidence Level

The degree of confidence in whether or not the true figure for the population lies within the confidence interval for the survey.

For example, a 95% confidence level indicates there is a 1 in 20 (5%) chance that the true population result falls outside the confidence interval range.


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