Key points: 1) The goal is not to figure out if Variation is better than Control (this is what classical hypothesis testing is about). The goal is to make the

Key points: 1) The goal is not to figure out if Variation is better than Control (this is what classical hypothesis testing is about). The goal is to make the revenue maximizing decision. If Variation and Control are identical, there is no harm in a false positive. 2) The author finds it desirable to allow the test to run for a variable amount of time, and stop it when statistical significance is achieved. This is called sequential testing. The rest is the details on how to actually accomplish these goals.