Appendix A.36

Two Proportions CI Calculator

Construct confidence intervals for the difference between two population proportions.

Confidence Interval for p₁ - p₂

Estimate the difference between two population proportions

Sample 1

Successes (x₁)

Sample Size (n₁)

p̂₁ = 0.2250

Sample 2

Successes (x₂)

Sample Size (n₂)

p̂₂ = 0.1667

Confidence Level

Requirements Met

Calculations

Point Estimate

Standard Error

Margin of Error

FORMULA (Not Pooled!)

95% Confidence Interval for p₁ - p₂

(-0.0211, 0.1378)

Interval Visualization

No Significant Difference

We are 95% confident that p₁ - p₂ is between -0.0211 and 0.1378. Since the interval contains 0, we cannot conclude there is a significant difference between the proportions.