Q: Two machines fill bottles. Samples: n₁ = 10, s₁ = 2; n₂ = 10, s₂ = 3. Test equal variance at α = 0.05. F = s₂²/s₁² = 9/4 = 2.25 (larger on top). df = (9, 9), critical F(0.05) = 3.18. 2.25 < 3.18: fail to reject - variances not proven different!