A confidence interval for a population standard deviation is a range of values that is likely to contain a population standard deviation with a certain level of confidence.
The formula to calculate this confidence interval is:
Confidence interval = [√(n-1)s2/X2α/2, √(n-1)s2/X21-α/2]
- n: sample size
- s2: sample variance
- X2: Chi-Square critical value with n-1 degrees of freedom
To find a confidence interval for a population standard deviation, simply fill in the boxes below and then click the “Calculate” button.
95% C.I. = [5.0637, 8.8119]
You can be 95% confident that the interval [5.0637, 8.8119] contains the true population standard deviation.