How to pick good metrics:
4 Business Metrics You Can’t Afford to Ignore
Measuring What Matters: How To Pick A Good Metric
The Lean Analytics Cycle: Metrics > Hypothesis > Experiment > Act
Amazon.com case study
Amazon’s business strategy and revenue model: A history and 2014 update
All the post from the author worth of reading.
Basic statistics
A website that may help: http://www.statisticshowto.com/post-index/