95% Confidence Interval: Mean 50, SD 10, n = 100
With mean 50, SD 10, and a sample of 100, the 95% confidence interval is approximately 48.04 to 51.96.
How to use this tool
- Enter sample mean (x̄), sample standard deviation (s), sample size (n) and z* (confidence level) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your lower bound and the full breakdown beneath it.
Calculate the 95% confidence interval for a sample mean of 50 with standard deviation 10 and sample size 100.
Frequently asked questions
- How do I choose the z* value?
- Common critical z-values: 1.645 for 90% confidence, 1.960 for 95%, 2.576 for 99%. These assume a large enough sample (n ≥ 30) so the Central Limit Theorem applies.