This simple free WordPress A/B split testing plugin is an effective tool for testing website landing page versions.
The premium version has built-in conversion tracking and automatic statistical confidence calculations. But you can do your own tracking to analyze and compare page performance by using Google Analytics conversion goal tracking (optionally in conjunction with the page value metric).
Download the Simple Page Tester WordPress Plugin here.
Bonus Tip: To more easily set up an A/B split test in WordPress, you can use a web page cloning plugin like Duplicate Post to make a copy of an existing “control” page, to use as a test page to set up the variables on.