[mojonixon]

Why do some of the ads get run more often than others? Seems like google would run the one with the highest click through rate more often. I'm not convinced all of these are statistically significant anyway, but I don't have R at the moment.

[byoung2]

There is a setting in Adwords for "rotate my ads evenly over time" that is necessary for accurate A/B testing. By default, Google shows the ads with the highest click rate more often, so you'll get a bias.