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A/B Split Test Statistical Significance Calculator

Calculate two tailed Z score, p value, relative conversion lift, and statistical confidence intervals (90%, 95%, 99%) between Control (Variant A) and…

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How to Use the A/B Split Test Statistical Significance Calculator

  1. 1 Enter Total Visitors and Conversions for Control Variant A.
  2. 2 Enter Total Visitors and Conversions for Treatment Variant B.
  3. 3 Review relative conversion lift percentage (%), two tailed Z score, and p value.
  4. 4 Check the automated decision banner: "Statistically Significant (>95%)" vs "Inconclusive / Keep Testing".

Methodology & Algorithmic Standards

Implements two-proportion pooled Z-test: $Z = \frac{p_B - p_A}{\sqrt{P(1-P)(1/n_A + 1/n_B)}}$ where $P$ is the pooled sample conversion rate. Computes Gaussian cumulative distribution function for two tailed p-values.

Frequently Asked Questions

What statistical confidence threshold should I aim for? ▼

The industry standard benchmark for CRO is 95% confidence (p < 0.05), which indicates only a 5% chance the observed conversion lift was due to random sampling variance.

Why should I not stop an A/B test too early? ▼

Stopping a test as soon as it reaches 95% significance (known as "peeking bias") dramatically inflates false positive error rates. Tests should run for at least 1 to 2 full business cycles.

Can I export this experiment report into Olevx Notepad? ▼

Yes! Click "Open in Notepad" to create a structured marketing experiment summary.

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