Gestation Periods of Humans. Gestation periods of humans have a mean of 266 days and a standard deviation of 16 days. Let y denote the variable “gestation period” for humans.

a. Find the standardized variable corresponding to y.

b. What are the mean and standard deviation of the standardized variable?

c. Obtain the z-scores for gestation periods of 227 days and 315 days.

Round your answers to two decimal places.

d. Interpret your answers in part (c).

e. Construct a graph similar to Fig. 3.20 on page 168 that shows your results from parts

(b) and (c).