F-distribution
The F distribution is used during Analysis of Variance (ANOVA) for hypothesis testing of data sets with more than 2 samples (or treatments). This sketch shows how F varies as dn, the degrees of freedom of the numerator, and dd, the degrees of freedom of the denominator, vary. The applet begins with df of the numerator animated and df of the denominator fixed at 25. Click on dn to stop that animation, and then turn on the animation of df of the denominator.