4. Suppose Y has 5 covariates X1, X2, X3, X4, X5 denote any model Y = P + Bixi + Bix; + BKXK + by (ijk). All the models can be listed as (0), (1), (2), (3), (4 ), (5 ), (12 ), (13 ), (14 ), (15), (23 ), (24 ), (25 ), (34 ), (35 ) , (45 ) , (123), (124), (125), (134), (135), (145), (234), (235), (245), (345), (1234), (1235), (1245), (1345), (2345), (12345). With n = 40, their respectively SSE are 95.2261, 73.3037, 95.2139, 90.8737, 69.2889, 73.6588, 73.0233, 70.9692, 53.2715, 42.4473, 90.8726, 69.2660, 73.2872, 63.9012, 72.6848, 25.0160, 70.5948, 52.8136, 42.4440, 49.9665, 42.4467, 0.2618, 63.7998, 72.4197, 24.7802, 24.4749, 49.3597, 42.4432, 0.2512, 0.2496, 24.3022, 0.2406. And their respectively BIC are 0.9596, 0.7902, 1.0517, 1.0050, 0.7338, 0.7950, 3