A/B testing is a method used by businesses to test different designs and formats of a web page to determine if a new web page is more effective than a current web page. Web designers tested a new call to action button on its web page. Every visitor to the web page was randomly shown either the original call-to-action button (the control) or the new variation. The metric used to measure success was the download rate: the number of people who downloaded the file divided by the number of peopl