2-Sample Proportion Test

Analyze Phase

Compare two independent proportions — e.g. defect rates from two production lines, pass rates from two sites. Tests whether the difference is statistically significant.

Input Summary Statistics

Group 1 Label

Successes (x₁)

Sample Size (n₁)

Observed Proportion

23.50%

Group 2 Label

Successes (x₂)

Sample Size (n₂)

Observed Proportion

30.50%

Alpha (α)

Proportion Comparison

Hypotheses

H₀: p₁ = p₂ (proportions are equal)

H₁: p₁ ≠ p₂ (two-tailed)

No Significant Difference

z = -1.577, p = 0.1149 ≥ 0.05. Fail to reject H₀ — no significant difference between the two proportions (23.5% vs 30.5%).

Test Statistics

Group 1 p̂

23.50%

Group 2 p̂

30.50%

Difference (p̂₁ − p̂₂)

-7.00%

z-statistic

-1.577

p-value

0.1149

95% CI Lower

-15.67%

95% CI Upper

1.67%

Significant?

95% CI for Difference (p₁ − p₂)

[-15.67%, 1.67%]

CI contains zero — no significant difference between proportions.