Confidence Interval Calculator for Two Means
Easily calculate the confidence interval for the difference between two population means. Input sample data and confidence level to find the interval.
Input Data
Enter the sample statistics for both populations and the desired confidence level to calculate the confidence interval for the difference in means.
Sample 1
Sample 2
Confidence Interval Result
Visualization
Confidence Interval Range
Understanding Confidence Intervals
A confidence interval is a range of values that estimates an unknown population parameter. For two means, it estimates the difference between the average values of two groups. For example, if we calculate a 95% confidence interval for the difference in average test scores between two teaching methods, and the interval is [2, 8], it suggests that we are 95% confident that the true difference in average scores lies between 2 and 8 points. A wider interval indicates more uncertainty, while a narrower interval suggests a more precise estimate. The confidence level (e.g., 95%) reflects how sure we are that the interval contains the true difference.