Lee Willis

This plugin lets you set up two different templates with differences that you think might increase conversions, serve these different templates up to users, and track their activity using custom segments in Google Analytics.
Alternatively you can use it to “choose” a particular theme by setting a URL parameter so you can experiment using different themes yourself (Particularly useful when developing your “split” themes!

SES Theme Split Test

Split test your wordpress theme, and track test using Google Analytics user defined values.

splitwit

This plugin automatically adds the SplitWit code snippet to your WordPress site. SplitWit lets you create a variation of your web page using our visual editor. It splits traffic between the original version and your variation. You can track key metrics, and let SplitWit determine a winner. No code needed.
After creating a SplitWit account, and starting a project, you can add the project ID code to the plugin’s settings page. That’s all you need to start improving your site’s conversion rate.
This plugin relies on SplitWit, a third-party service. The SplitWit service adds code to your website to run A/B experiments. It also collects data about how users interact with your site, based on the metrics you configure.
SplitWit Terms of Service: https://www.splitwit.com/terms-of-service 
SplitWit Privacy Policy: https://www.splitwit.com/privacy-policy

SplitWit

Optimize your website for maximum convertibility. This plugin lets you use SplitWit to run experiments on your WordPress website.

SES Theme Split Test vs SplitWit