Links

Videos

Measures of Central Tendency  (time: 2:00)
http://www.youtube.com/watch?v=FkS5DFXcioQ

Medians and Quartiles (time: 5:42)
http://www.youtube.com/watch?v=3pMRePkhQfM

Boxplots (time: 4:15)
http://www.youtube.com/watch?v=ETB-52xXeBs

History

This is one of the best all around sites that I have found. It is titled "The MacTutor History of Mathematics Archive."
http://www-history.mcs.st-and.ac.uk/~history/

This is an award-winning site that links to all sorts of mathematics information.
http://archives.math.utk.edu/

Quetelet:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Quetelet.html

Reference Topics

This site is a glossary of statistical terms:
http://www.stat.berkeley.edu/users/stark/SticiGui/Text/gloss.htm

This site provides some practice with the mean:
http://www.robertniles.com/stats/mean.shtml

This site provides some practice with the median:
http://www.robertniles.com/stats/median.shtml

This interactive site calculates the mean and median for a data set.
http://www.svgs.k12.va.us/math/Statistics/Histogram/Mean.html

Mean, median, and mode discussion.
http://www.shodor.org/interactivate/discussions/sd1.html

This is not a fancy site, but is interesting. It is more advanced than the textbook.
http://www.physics.csbsju.edu/stats/