University of California, Berkeley: Philip Stark's SticiGui: "Chapter 24: Sampling"
Read Chapter 24 for an explanation of what sampling means in statistics and its possible biases when collecting data for a sample. There are several exercises and Java applets embedded in the text that are meant to further reinforce your learning. Do not skip these exercises! For instructions on how to navigate these exercises, see "Special Instructions on SticiGui Exercises and Java Applets” in the "Course Information” section above.