Sample Size for Two-Sample Proportion Test

Size your study to compare two binomial proportions with the power you need. Set the expected proportions in each group, pick exact or normal methods, and choose the allocation ratio to get the required sample size per group.

Ideal for

• A/B tests with binary outcomes
• Clinical response rates across treatment arms
• Manufacturing pass rates between two processes

Parameters to supply

• Group proportions p1 and p2
• Alpha, sidedness, and target power
• Allocation ratio between the two groups