Group=j Uj= exp(wjφ) [95% CI]
Gamma: gestational Age ( ≤ 28) 1.575[0.9207, 2.695]
Gamma: gestational Age (28, 30] 1.254[0.6325, 2.487]
Gamma: gestational Age (30, 32] 1.135[0.6568, 1.960]
Gamma: gestational Age (32, 34] 0.527[0.2646, 1.049]
Gamma: gestational Age (34, 37) 0.509[0.2357, 1.099]
Table 6: Common frailty term of premature infants in categories of preterm by gestational age.