Just a very short message to direct you to my article on statistical significance over on the Kissmetrics blog. The emphasis is on intuitive means to understanding the key ideas.
Check Out My Guide to Statistical Significance on Kissmetrics
Fun, example-filled guide, aimed at building intuition
Ways metrics mislead you; how to overcome low reach/low quality score/high CPC etc.
SEO-ed *text* enters you into the main event, but you might also want to compete in Google’s alternative races, such as Google Images, Google Videos, or Google Maps.
How to structure campaigns, why to not delete data, when to schedule reviews