(Data file: cakes) For the cakes data in Section 5.3.1, we fit the full second-order model,
E(Y|X₁ = X₁, X₂ = X2 ) = ß0 + B₁x1 + B2x² + B3X2 + B4x² + B5X1X2
Compute and summarize the following three hypothesis tests.
NH: B5 = 0 vs. AH: ß5 ≠ 0
NH: B₂ = 0 vs. AH: B₂ ≠0
NH: B₁ = B₂= B = 0 vs. AH: Not all 0