Behavioral Research: Statistical Methods

If t-tests answer 'do these two groups differ?', ANOVA answers it for three or more. The trick: instead of running every pairwise t-test (and paying a brutal Type I tax), ANOVA invents a single number — F — that asks 'is the variability *between group means* bigger than the variability *inside groups*?' Under H₀ (all means equal) F sits near 1; under H₁ it grows. One omnibus test, one α, no matter how many groups. The cost: F tells you *somewhere* the means differ, not *where* — that's what post-hoc tests are for.