[notice type=attention]Note: the website introduced below has been moved to http://animation.yihui.name.[/notice]
This afternoon I went to the Beijing Custom to give a lecture on sampling techniques as well as my R program. Actually I didn't make any preparations until late in this morning. When I finished my lunch, I made some animated pictures to illustrate these four kinds of sampling methods: simple random sampling, stratified sampling, cluster sampling and systematic sampling.
After I came back to school, I added these animations to my little project "Animated Statistics Using R". You may see them here.