Answer:
218 and 314 days
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 266
Standard deviation = 16
About 99.7% of all pregnancies last between what interval?
Within 3 standard deviations of the mean. So
266 - 3*16 = 218 days
266 + 3*16 = 314 days
218 and 314 days
