Visual ANOVA is a simple little program that puts the theory on ANOVA into a simple visual whole. It assumes that you've read the Even if your understanding is incomplete at this time, it is worth playing with Visual ANOVA since that may clear up the big picture for you.
This virtual applet simulates randomly drawing numbers from a box. You can choose which numbers you would like to choose from and the number of draws. The applet has the option to show theoretical probability and displays the results in histogram form.
This online, interactive lesson on foundations provides examples, exercises, and applets which review the algebra of sets and functions, general relations with special emphasis on equivalence relations and partial orders, and some basic combinatorial structures such as permuations and combinations.
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).