I have been working in the last years with statistics and have gone pretty deep in programming with R. I have however always felt that I wasn't completely grasping what I was doing, still understanding all passages and procedures conceptually.
I wanted to get a bit deeper into the math behind it all. I've been looking online for texts and tips, but all texts start with a very high level. Any suggestions on where to start?
To be more precise, I'm not looking for an exaustive list of statistical models and how they work, I kind of get those. I was looking for something like "Basics of statistical modelling"