Question

The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 261 days and standard deviation 12 days. Use a normal z-table to answer all questions below. If not,your answers may be marked as incorrect due to rounding issues.

(a) What proportion of pregnancies last less than 270 days (about 9 months)? (Use 4 decimal places)

(b) What proportion of pregnancies last between 240 and 270 days (roughly between 8 months and 9 months)? (Use 4 decimal places)

(c) The longest 20% of pregnancies last days or longer. (Round to an integer.)

(d) What are the quartiles of the distribution of lengths of human pregnancies? Q1 = days (Round to an integer.) Q3 = days (Round to an integer.)

Answer 1