Fittest plugin for WordPress lets you experiment with different variations of content on your site.
Install Fittest either via the WordPress.org plugin directory, or by uploading the files to your server After activating Fittest, you can start experimenting right away.
1. Choose the menu option Experiments > Add New
2. Pick the pages you want in the experiment
3. After publishing the experiment add the experiment to the menu of choice (Make sure you have Experiments in your screen options)