logit =
= -14.6889 +
(8.6774 * (1/ (birthweight in kilograms))) +
(1.4414 * (1 if Apgar at 5 minutes < 7, 0 if Apgar >= 7) +
(1.0898 * (1 if <5th% for gestational age, 0 if >= 5th% for gestational age) +
(0.7422 * (SNAP) * (1 if SNAP <= 15, 0 if SNAP > 15)) +
(0.6251 * (SNAP) * (1 if SNAP >= 16 and <=20, 0 if SNAP < 16 or > 20)) +
(0.4674 * (SNAP) * (1 if SNAP >= 21 and <=27, 0 if SNAP < 21 or > 27)) +
(0.4073 * (SNAP) * (1 if SNAP >= 28, 0 if SNAP < 28 )) -
(0.5429 * (SNAP/birthweight) * (1 if SNAP <= 15, 0 if SNAP > 15)) -
(0.4088 * (SNAP/birthweight) * (1 if SNAP >= 16 and <=20, 0 if SNAP < 16 or > 20)) -
(0.2809 * (SNAP/birthweight) * (1 if SNAP >= 21 and <=27, 0 if SNAP < 21 or > 27)) -
(0.2399 * (SNAP/birthweight) * (1 if SNAP >= 28, 0 if SNAP < 28 ))
risk of mortality =
= EXP(logit) / (1 + EXP(logit))
chance for survival =
= 1 - (risk of mortality)
