University of Helsinki
Visualizations, specially dynamic ones can help in the understanding of statistical concepts. You can find some wonderful examples at a web site called R <- psychologist.
Do you understand hypothesis testing? and the controversy behind it?
Understanding Statistical Power and Significance Testing
Do you understand confidence intervals (CI)?
Interpreting Confidence Intervals
When you see a scatter plot are you able to guess a value for the correlation?
Interpreting Correlations
Have fun! and get some new insights about statistical tests.