The lengths of pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. if the length of pregnancy is in the lowest 4%, then the baby is premature. find the length that separates premature babies from those who are not premature.

Premature babies are represented by the area of the Normal distribution curve to the left of 4%.

At 4% (or 0.04), Z is approximately -1.75 (from the Standard Normal Probabilities).
Now,

Length that separates premature babies from the rest = mean-Z*SD
Where, Mean = 268 days, SD = 15 days and Z= -1.75
Substituting;

Length of reparation = 268-1.75*15 = 241.75 days

Idon’t know actually i’m in 5th grade and don’t know