ANOVA F Statistic
The one-way ANOVA test statistic is
$$ F = \frac{MSTreat}{MSE}. $$Under $H_0: \mu_1 = \cdots = \mu_k$, this statistic has an $F_{k-1, N-k}$ distribution under the ANOVA assumptions.
Large values of $F$ indicate that between-treatment variation is large relative to within-treatment variation, which is evidence against $H_0$.