[rainforest]

> I don't understand why an entire elementary statistics pseudo-textbook is bolted on at the end, forming the entire back half of the text

It's quite difficult to talk about empirical software engineering without discussing methods, after all papers like [1] were deemed necessary 20 years ago and still the occasional meta-paper is published about correct design of experiments or analyses. As someone who worked in the field it doesn't seem particularly surprising to see some treatment - there are a handful of papers in my former subfield that are oft-cited because they describe a statistical procedure/experiment design consideration, but they also bundle the explanatory stats "for free".

I would hazard a guess that the intent of these chapters is to equip the reader with enough background that they could replicate or run some of the experiments in the book to try to specify findings/experiments to their own organisations. I'd follow that with an assumption that the author felt that chapter 13 needed background, and recursed until they'd finished writing a textbook.

[1] Kitchenham et al. "Preliminary guidelines for empirical research in software engineering" 2001: http://www.ehealthinformation.ca/wp-content/uploads/2014/07/...