6.66 Gestation times For 5459 pregnant women using Aarhus University Hospital in Denmark in a two-year period who reported information on length of gestation until birth, the mean was 281.9 days, with standard deviation 11.4 days. A baby is classified as premature if the gestation time is 258 days or fewer. (Data from British Medical Journal, July 24, 1993, p. 234.) If gestation times are normally distributed, what’s the proportion of babies born in that hospital prematurely?