Using the Central Limit Theorem. In Exercises 5–8, assume that females have pulse rates that are normally distributed with a mean of 74.0 beats per minute and a standard deviation of 12.5 beats per minute (based on Data Set 1 "Body Data" in Appendix B). If 1 adult female is randomly selected, find the probability that her pulse rate is less than 80 beats per minute. If 16 adult females are randomly selected, find the probability that they have pulse rates with a mean less than 80 beats per minute. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30?