A slideshow presentation with two good examples on using the Z-test for the difference between two means. Gives some good "plain language" interepretations of what "statistically significant difference" means.
This chapter of the HyperStat Online Textbook presents six sections on probability including conditional probability, unions, intersections, and the Binomial distribution. A link to exercises for the chapter is available, as well as a link to an applet that demonstrates the approximation of the binomial with a normal distribution (in section 5).
