[DougN7]

I can answer from personal experience. I'm a dev at a tiny startup. I took statistics at college 20 years ago but haven't used it since the final exam, and remember little other than sample size is critical. I've figured out through recent experience that you need to let a test run a while - results seem to flip flop for the first few thousand visitors. I use tools like VWO because it makes it simple to run a simple one variable test, and I'm happy with the results (though ignorance is bliss, so maybe others would not be so content).