Your test reports that variant B converted at 3.6% against 3.2%. That single number is the middle of a range, and the range matters more than the point.

What You're Told	What It Means	Ship?
+12%, range +8% to +16%	Confidently positive, decent size	Yes
+12%, range +0.5% to +24%	Probably positive, but could be trivial	Maybe, consider running longer
+2%, range -1% to +5%	Could be a small gain, could be nothing	No clear answer. Don't claim a win.
+0.3%, range +0.1% to +0.5%	Real, confidently tiny	Only if it costs nothing to maintain
-9%, range -14% to -4%	Confidently worse	No. And worth understanding why.

Ask your tool or your analyst for the range, not just the headline number. A wide range means you don't really know the size of the effect, and that's important information, particularly when someone wants to build a forecast on it.

A/B Testing for Product Managers

Module 1Why Most A/B Tests Waste Three Weeks

Module 2Is This Even Worth Testing?

Module 3Writing a Hypothesis You Can Be Wrong About

Module 4Choosing the Metric

Module 5How Long It Needs to Run

Module 6Running It Without Ruining It

Module 7Reading the Result

Module 8Deciding and Shipping

Module 9The Six Ways Tests Lie

Module 10When A/B Testing Is the Wrong Tool

Module 11Final Project: Design, Run and Report One Real Test

Module 12Appendix: The Prompt Library

Module 13Glossary: Words Explained

Effect Size and the Range