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)s
2
/X
2
α/2
, √(n-1)s
2
/X
2
1-α/2
]
where:
n: sample size
s
2
: sample variance
X
2
: 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.
n
(sample size)
s
(sample standard deviation)
Confidence level
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.