R learning courses

Some of the materials are widely distributed, but some of them are not. I list a few websites that I find really useful in learning R and refreshing memories on statistical analysis.

1) Missing data

2) Regression and OLS modeling (Dave Armstrong在ICPSR的講稿和R codes)

3)  a first graduate course in political methodology (Gary King的哈佛量化統計課程

4) Hands-on practices of R

5) R for Data Science