Confidence Interval Calculator

What is Confidence Interval?

A confidence interval is a range of values that can include the actual value of the parameter studied in statistics. It is created using observed data and estimated at the desired confidence level. For instance, a 95 percent confidence level refers to the accuracy of the estimating process rather than the degree of certainty that the computed confidence range accurately represents the study parameter. Before calculating the confidence interval, the desired confidence level is chosen. It displays the percentage of confidence intervals that, when formed given the selected confidence level across an infinite number of independent trials, will include the parameter's actual value.

Typically, confidence intervals are written as (some value) ± (a range). The range can be expressed as a percentage or as an absolute value. The range of values is another way to write it. For instance, the following confidence intervals are all equivalent:

20.6 ±0.887

or

20.6 ±4.3%

or

[19.713 – 21.487]

About This Tool:

With the assumption that the sample means most likely follows a normal distribution, use this calculator to determine the confidence interval or margin of error. The computation is done in real-time when you provide the sample group, mean, and standard deviation.

How To Use This Tool To Find The Confidence Interval?

To find the confidence interval:

• Enter sample mean (x)
• Enter sample size (n)
• Enter standard deviation (s)
• Select confidence level from the list and click on calculate.

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