University of California, Berkeley: Philip Stark's SticiGui: "Chapter 19: Probability Meets Data"
Read Chapter 19, which unites probability with samples and explains the nature of a probability distribution. 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.