Confidence Interval for the Difference in Proportions Calculator

A confidence interval for a difference in proportions is a range of values that is likely to contain the true difference between two population proportions with a certain level of confidence.

The formula to calculate the confidence interval is:

Confidence interval = (p₁ – p₂) +/- z*√(p₁(1-p₁)/n₁ + p₂(1-p₂)/n₂)

where:

• p₁, p₂: sample 1 proportion, sample 2 proportion
• z: the z-critical value based on the confidence level
• n₁, n₂: sample 1 size, sample 2 size

To find a confidence interval for a difference between two population proportions, simply fill in the boxes below and then click the “Calculate” button.

n₁ (sample 1 size)

p₁ (sample 1 proportion)

n₂ (sample 2 size)

p₂ (sample 2 proportion)

Confidence level

95% C.I. = [0.0236, 0.2964]

You can be 95% confident that the interval [0.0236, 0.2964] contains the true difference between the population proportions.