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.
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.
Which is the name of the statistical test or technique used by the calculator to estimate CI for the differebce of two proportions?
Thank you!
this is a handy calculator. thanks.
how to calculate CI for a difference between two proportions of the same population?
excellent for use in determining sample size for trials / deeply appreciated