We’re making some changes to MailChimp’s A/B email testing interface. In the old interface, some people (me) got a little confused because the interface was ambiguous (I suck at math) and so it was hard to calculate the size of each group (A vs. B).

Aarron, our user interface dude, felt sorry for those users (me), and so he made it all visual:

These changes will go live with MailChimp v3.3, sometime in early October.