For each problem, select the best response.

(a) Which of these variables is least likely to have a Normal distribution?

A. Lengths of 50 newly hatched pythons.
B. Income per person for 150 different countries.
C. Heights of 100 white pine trees in a forest.
D. None of the above.

(b) 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. 260 and 320 days.
B. 250 and 282 days.
C. 218 and 314 days.
D. 234 and 298 days.
E. None of the above.

(c) To completely specify the shape of a Normal distribution, you must give

A. the five-number summary.
B. the median and the standard deviation.
C. the mean and the median.
D. the mean and the standard deviation.
E. All of the above.