Analyze A/B Test Results with Statistical Rigor and Business Recommendations
Get a rigorous statistical analysis of your A/B test results with significance testing, power analysis, and business recommendations.
๐ The Prompt
You are an expert data analyst and statistician specializing in experimentation and A/B testing. Analyze the following A/B test results and provide a comprehensive, statistically rigorous evaluation with actionable business recommendations.
**Experiment Details:**
- Experiment name: [EXPERIMENT_NAME, e.g., 'Checkout Button Color Change']
- Hypothesis: [HYPOTHESIS, e.g., 'Changing the checkout button from blue to green will increase conversion rate by at least 5%']
- Primary metric (KPI): [PRIMARY_METRIC, e.g., conversion rate, click-through rate, revenue per user]
- Secondary metrics: [SECONDARY_METRICS, e.g., bounce rate, average order value, time on page]
- Test duration: [DURATION, e.g., 14 days]
- Traffic split: [SPLIT, e.g., 50/50]
**Results Data:**
- Control group (A): [CONTROL_SAMPLE_SIZE] users, [CONTROL_CONVERSIONS] conversions
- Treatment group (B): [TREATMENT_SAMPLE_SIZE] users, [TREATMENT_CONVERSIONS] conversions
- Any additional metric data: [ADDITIONAL_DATA]
**Please perform the following analysis:**
1. **Descriptive Statistics**: Calculate conversion rates for both groups, the absolute and relative lift, and confidence intervals for each group's conversion rate.
2. **Statistical Significance Testing**: Conduct a two-proportion z-test (or appropriate test). Report the z-score, p-value, and whether the result is significant at [SIGNIFICANCE_LEVEL, e.g., 95%] confidence level. Explain what these numbers mean in plain language.
3. **Power Analysis**: Assess whether the sample size was adequate to detect the hypothesized minimum detectable effect (MDE). If underpowered, calculate how many more samples would be needed.
4. **Practical Significance**: Beyond statistical significance, evaluate whether the observed effect size is practically meaningful for the business. Estimate the projected annual impact in terms of [BUSINESS_METRIC, e.g., additional revenue, extra conversions].
5. **Segmentation Analysis**: Suggest 3-4 key segments (e.g., device type, new vs. returning users, geography) to cut the data by, and explain what differential effects to look for.
6. **Validity Threats**: Identify potential threats to the experiment's validity including novelty effects, sample ratio mismatch, seasonality, or selection bias.
7. **Final Recommendation**: Provide a clear GO / NO-GO / ITERATE recommendation with justification and suggested next steps.
Format the output with clear sections, include the mathematical formulas used, and present a summary dashboard in a table format.
๐ก Tips for Better Results
Always input raw numbers (sample sizes and conversions) rather than pre-calculated percentages to allow the AI to verify calculations independently.
Mention any known issues during the test period (site outages, marketing campaigns, holidays) so the AI can flag potential confounding factors.
Ask for follow-up analysis on specific segments if the overall result is inconclusive โ hidden effects in subgroups are common.
๐ฏ Use Cases
Product managers, growth analysts, and marketing teams who have completed an A/B test and need a thorough statistical analysis before making a ship/no-ship decision.