My situation is I have a list of people that were included in a marketing campaign. Half the list got version 1 of an email and the other half got version 2. Then people either bought the product or didn't.

Lets say both lists had 200 people. And in list 1(version 1 email) 20 bought the product. and in list 2 24 people bought the product.

In absolute terms it seems the version 2 email is more successful. Can someone tell me how to determine statistical significance for this test? and additionally, if you know of any resources where I can read/learn more about the topic of knowing which test to run in which scenario.

Thanks