Confidence Interval for the Difference in Proportions Calculator

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)
  • 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.

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.

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