Statistics

AB Test Calculator

Compare two conversion rates for statistical significance.

Calculated Output

Relative uplift (%) 30

z-statistic 2.103

Two-tailed p-value 0.0355

Formula: Two-proportion z-test

Step-by-Step Breakdown

1. Values used:

2. Group A visitors = 1,000

3. Group A conversions = 100

4. Group B visitors = 1,000

5. Group B conversions = 130

7. Relative uplift = 30%

8. z-statistic = 2.103

9. Two-tailed p-value = 0.0355

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The math behind it

A two-proportion z-test compares the conversion rates; a p-value below 0.05 signals a real difference.

10% vs 13% on 1000 each gives z about 2.04, p about 0.041 (significant).

How big a sample do I need?

Use a sample-size calculator based on your baseline rate and the uplift you want to detect.