95% Confidence Interval: Standard Normal, n = 1000
For a standardized variable (mean 0, SD 1) with 1000 observations, the 95% CI is approximately −0.062 to 0.062.
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 large sample of 1000 drawn from a standard normal distribution (μ = 0, σ = 1).
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.