Normal Confidence Interval Calculator
Enter the sample mean, standard deviation, sample size, and confidence level to calculate the normal confidence interval.
* Note: Confidence level must be between 0 and 100 (exclusive).
Step 1: Enter Parameters
e.g., 0
e.g., 1
e.g., 30
e.g., 95 for 95% confidence
How It Works
The confidence interval for the mean is calculated as: $$ \bar{x} \pm z_{\alpha/2} \cdot \frac{\sigma}{\sqrt{n}}, $$ where \( z_{\alpha/2} \) is the critical value from the standard normal distribution.
The critical value \( z_{\alpha/2} \) is determined by the desired confidence level.