A good place to start training in statistical thinking and reasoning is of course any text book. Good “open textbooks” can be found online, such as OpenIntro Statistics.
Plenty of great online introductory courses on statistics, probability, data analysis, etc. are also available. For example, Coursera provides high-quality massive open online courses (MOOC’s) on topics such as data analysis, computational analysis, R (statistical programming language), and network analysis. To begin with, take a look at Scott E. Page’s Model Thinking (University of Michigan), Andrew Conway’s Statistics One (Princeton University), or Data Analysis and Statistical Inference (Duke University) taught by Mine Çetinkaya-Rundel.
Khan Academy’s free tutorials on statistics and probability are of great quality and interest for those who want to learn more about the mathematics of statistical reasoning and methods. Khan Academy is an educational website hosted by Salman Khan, consisting of 4,000 of his micro lectures on various topics.
Good online sources for familiarizing oneself with communication theories and models are also available. Communication theories can serve as testable theories or models for building up own one’s own theoretical framework.
- Communication theories is a comprehensive resource of different communication theories maintained by Twente University. It is a well-organized catalog of different theories arranged according to their level and purpose. Also the most important references and practical examples are presented for some theories.
- Theory for communication is a “work in progress” web page by the University of Colorado Boulder and it comprises a massive amount of information about communication theories. There are plenty links and lectures concerning important theorists, different research paradigms, and so forth.
- A First look at Communication Theory is a web site for a communication theory text book by Em Griffin including an overview of many of the important theories in the area of communication studies.