I have learned basic and somewhat intermediate R. I have used the resources my Dr gave us. But I have also read the book "YaRrr! Pirate's Guide to R" until chapter 15. I have learned how to import and tidy datasets, do plotting, t-tests (hypothesis testing), correlation test, regression analysis, goodness of fit test and chi-square test of independence in R. R also serves as a programming language, and I was messing around with it for a while before all the tests.
