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# Confidence Interval Width Calculator

A confidence interval in short CI is a type of interval estimate of a population parameter. Sample size, standard deviation and the confidence level are the three major things that affect the confidence interval width. As the sample mean increases, the width remains the same. As the sample standard deviation decreases, the width of the interval decreases. As the sample size increases, the interval and its width decrease, thus providing a more precise estimate of the population value.

Here is an online statistics calculator to estimate the confidence interval width for known sample size.

## Find Confidence Interval Width for Known Sample Size

A confidence interval in short CI is a type of interval estimate of a population parameter. Sample size, standard deviation and the confidence level are the three major things that affect the confidence interval width. As the sample mean increases, the width remains the same. As the sample standard deviation decreases, the width of the interval decreases. As the sample size increases, the interval and its width decrease, thus providing a more precise estimate of the population value.

Here is an online statistics calculator to estimate the confidence interval width for known sample size.

#### Formula:

If (n>=30), CI = x ± Zα/2 × (σ/√n) If (n<30), CI = x ± tα/2 × (σ/√n) Where, x = Mean σ = Standard Deviation α = 1 - (Confidence Level/100) Zα/2 = Z-table value tα/2 = t-table value CI = Confidence Interval

Online calculation of Confidence Limits for Mean is made easier.