AdWords Campaign Experiments allow you to test changes to account for a portion of the auctions
Test changes to your account for a portion of the auctions that your ads participates in. – CORRECT
Automate different images and text on your site to understand what converts most effectively.
Receive written feedback from users based on their experience on your site.
Request a formal analysis from Google’s Campaign Experiments team that isolates the effect of online advertisements on offline purchases.