This calculator creates a confidence interval for a population mean using the following formula:
Confidence Interval = x +/- z*(s/√n)
where:
- x: sample mean
- z: z-value that corresponds to confidence level
- s: sample standard deviation
- n: sample size
To create a confidence interval for a population mean, simply fill in the values below and then click the “Calculate” button:
90% Confidence Interval: (5.896, 28.104)
95% Confidence Interval: (3.770, 30.230)
99% Confidence Interval: (-0.388, 34.388)
This site looks great – thanks for all the hard work!
If I wanted to use this to find the confidence interval for an intervention, would I be using a value of n which looks at the entire sample (ie control and treatment branches) or just the treatment one?
Sorry for the noob question!
This calculator is not correct — it is using the “sample” std deviation as the **population** std deviation.