3 points) For each problem, select the best response. (a) The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 266 days and standard deviation 16 days. About 95% of all pregnancies last between A. 234 and 298 days. B. 260 and 320 days. C. 218 and 314 days. D. 250 and 282 days. E. None of the above. (b) The scores of adults on an IQ test is approximately Normal with mean 100 and standard deviation 15. Corinne scores 118 on such test. Her z-score is about A. 1.2 B. 7.87 C. 0.67 D. 18 E. None of the above. (c) To completely specify the shape of a Normal distribution, you must give A. the mean and the median. B. the five-number summary. C. the median and the standard deviation. D. the mean and the standard deviation. E. All of the above.